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Their Application Especially to Medicine - 



Professor of Chemistry and Diredlor of the Laboratory, College 

of the City of New York, formerly of the University 

of North Carolina. 

Published by 

Williams, Brown & Earle 



Copyrighted by 

Williams, Brown & Earle, 





Q A 


To fill a demand for an inexpensive non-mathematical 
work on the subject of radium and its application in medicine, 
arrangements were made for the publication of this book. 
At that time the excellent treatises of Rutherford and Soddy 
had not appeared. To anyone purposing the prosecution of 
investigations, these works are indispensable. One treats the 
phenomena of radio-activity from the point of view of a 
physicist, while the other looks at them more with the eyes of 
a chemist. The appearance of these works has made it neces- 
sary to alter this book somewhat. The technical details have 
been given so admirably by these co-laborers that it has been 
thought just as well to omit much here. This book emphasizes 
a phase naturally but hinted at by them, namely, the applica- 
tion of radio-active substances in medicine. The writer is 
not in a position to harmonize the contradictory evidence given 
in reputable medical journals as to the therapeutic uses of the 
salts of radium, consequently the observations have been impar- 
tially reported. Physicians of prominence, who ha-ve had 
much to do with the use of this novel substance in their prac- 
tice, have been good enough to revise the chapter bearing upon 
that phase of the subject. 

It has been deemed advisable for comparison to annex a 
short chapter on other therapeutic radiations. 

As many physicians will have neither the time nor the 
opportunity to study the larger works, sufficient of the general 
subject has been presented for a fairly clear conception of our 
present knowledge of these startling, perhaps revolutionary, 

Although the work makes no pretense at completeness, all 
known sources of information have been freely drawn upon. 
In most cases due credit has been given. 

The bibliography, which was prepared, has been omit- 
ted. A most complete index to the extensive literature of 
radium by Dr. George F. Kunz is in press for the United States 
Geological Survey. 

Dr. Fritz Zerban and Mr. Frederick E. Breithut have gen- 
erously followed the proof -sheets. Mr. N. R. Graham was 
good enough to prepare the index. 

New York, 1905. 


Chapter Page 

I. The Phenomenon of Radio- Activity, . . . i 

II. The Extraction of Radium Salts ; Properties, 

Physical and Chemical of Radium, . . 22 

III. Other Radio- Active Substances ; Uranium, Tho- 

rium, Polonium, Actinium, Carolinium, 
Thorium X, Radio-Tellurium, Emaniutn, 
and Radio- Active Lead. The Sources of 
Radio-Activity, ...... 46 

IV. The Emanations of Radium and Induced Radio- 

Activity . Ex- Radio, . . . . 69 

V. The Theories of Radio- Activity, ... 94 

YI. The Physiological Properties and Therapeutic 

Applications of Radio- Active Substance, . 115 

VII. Other Therapeutic Radiations, . . . .142 
Index, ... ..." . . .. .\ ". . . .153 

Radium and Radio-Active Substances. 



If there be one thing which may be said to characterize 
science and its progress, it is evolution, or growth. Practi- 
cally all the great movements of science and its modern mar- 
vels are linked to the past. The phenomenon of radio-ac- 
tivity, which has astonished a civilization accustomed to 
wonders, is no exception. 

Without going too far back, attention may be called to 
the now well known fact that an electric spark passes through 
the air in a zigzag line, the length of which varies with the 
distance between the charged and uncharged bodies. The 
intensity of the spark varies with the charge, a corresponding 
difference being observed, as when the hand is passed over a 
cat's fur or surcharged clouds relieve themselves in a violent 
flash of lightning. The discharge presents a very different 
appearance, however, when the air is rarified, as originally 
investigated by Gassiott. 

Geissler, of Bonn, was the first to imprison gases under 
diminished pressure in tubes provided with electrodes, that is, 
conducting terminals by which the discharge may be carried in 
or cut. Geissler tubes are so exhausted that there exists an 
internal pressure of about one-thousandth of an atmosphere. 
The discharge, visibly passes (Fig. i) between the anode 
(positive) and cathode (negative), the one terminal being of as 


much importance apparently as the other. Plucker has shown 
that the color of the light produced is not dependent upon the 
substance of the electrodes. It varies with the nature of the 
gas or vapor, being crimson with hydrogen and purple-red 
with nitrogen, and so on. 

In 1876 Crookes made an elaborate investigation of the 
phenomena produced by the electric discharge in much higher 
vacua 1 . The pressure within the Crookes tubes is about one 
thousandth that of the Geissler tubes, or one-millionth of an 
atmosphere, and the path of the discharge is no longer visible. 
The discharge is independent of the anode and appears to pro- 
ceed from the cathode alone Ifi^f) . Further, the luminous 

Fig. i. Fig. 2. 

Fig. I. In a Geissler tube the discharge visibly passes between anode 
and cathode, the location of the former being of little importance. 

Fig. 2. In a Crookes tube the cathode rays are projected in straight 
lines from its surface ; their presence is noted by the fluorescence of the 
walls of the tube opposite the negative terminal. 

effect upon the glass is directly opposite the cathode, which 
indicates that these rays move in straight lines and strike upon 
the glass exactly opposite that electrode. With the Geisslei 

i. Phil. Trans. CLXX, 135, 641 ; Nature XX, 419, 436. 


tubes, on the other hand, the discharge may be made to follow 
devious paths, depending upon the shape of the apparatus, 
thus prod-ttctttg exquisite-effects'. ('ig,_lL 

The production of light without any considerable heat 
by the action of such rays was designated luminescence by E. 
Wiedemann. The color of the light depends not upon the 
gaseous contents of the tubes, but the solid material upon 
which the rays impinge. Some diamonds, for example, glow 
spterrdidly white, while coral gives an intensely brilliant red- 
dish or purplish luminescence 

Two other interesting properties of the cathode rays must 
be mentioned. A tube was prepared by Crookes (Fig. 4), 

Fig. 3- 
Fig. 3. In a Geissler tube the current may pass devious paths. 

Fig. 4. 

Fig. 4. A Crookes tube provided with a window in an aluminum- 
shield and fluorescent screen. The cathode rays projected, on the pas- 
sage of the current, as a beam upon the screen, appear as a ribbon of light 
indicated by the shading. On bringing the pole of a strong magnet 
above, the cathode rays are attracted or repelled according to the polar- 
ity. The ribbon is bent, the extent of the bending depends upon the 
vacuum, strength of the magnet, etc. 


whereby a stream of rays could be caused, by means of a 
narrow slit in a mica or aluminum partition, to play upon a 
screen of some substance which would glow under their influ- 
ence. The rays may be deviated by means of a magnet 
being attracted or repelled, according to the polarity. An 
electric field has the same influence ; these rays are, therefore, 
different from light rays. Again, it may be demonstrated 
easily that these rays carry considerable energy with them. 
By using a concave cathode, the rays which are shot out at 
right angles to the surface, may be brought to a focus with the 
production of heat at that point. On making the current suffi- 
ciently strong, Sir William Crookes was able to fuse platinum- 
iridium by this means. Perrin calculated that the amount of 
energy produced by the impact of a kilogram of the corpuscles, 
assuming them to be particles, woulcTraise to the boiling point 
in one second a lake 1,000 hectares (2,500 acres) in area and 

5 metres deep. 

Crookes' s explanation of the phenomena recounted rests 
upon his assumption of material particles of residual gas in 
the tube, which being negatively electrified at the surface of 
the cathode are repelled by it and driven away with a high 
velocity. In support of the electrified radiant matter hypo- 
thesis, he devised a variety of tubes for demonstrating the 
mechanical action of the particles. Only one tube may be 
referred to here,. It is known as the railway tube (Fig. 5). 
This tube contains a paddle wheel, whose axle rests upon a 
pair of glass rails. By making the proper terminal the 

Fig- 5- 

Fig. 5. Crookes' "railway tube." The cathode rays coming from one 
terminal drive the paddle wheel to the other end of the tube ; by revers- 
ing the polarity, without disturbing the level of the tube, it is driven 


cathode, the fly may be driven in either direction. Apparently 
in protest to the term ''radiant matter," which implied the 
material nature of the particles, the Germans through the 
work of Goldstein, Wiedemann, and Lenard, invented the 
term, " cathode ray," which is in common use at present. 

In 1895 Perrin 1 practically proved that the Crookes ray 
consists of streams of negatively electrified material particles. 
J. J. Thomson 2 confirmed these observations in 1897 and later 
actually measured their mass, electric charge, and the velo- 
city of their movement. For full details one is referred to the 
original papers. For our purpose, suffice it to say, he 3 learned 
that the mass of each of the particles constituting the cathode 
rays is only one-thousandth the mass of the hydrogen atom, or 
2.3xio" 24 milligram* and it has a velocity varying from one to 
four-tenths that of light, 2.2-3.6xio 9 centimetres per second, 
depending upon the degree of exhaustion in the tube. 

Thomson, further, showed that the ratio of the mass of a 
particle to its electric charge is independent of the nature of 
the gas and the electrodes. These particles, as a consequence, 
may be said to constitute a kind of matter previously unknown. 
The old Newtonian corpuscular theory being so strongly sug- 
gested, these particles have been called " corpuscles." They 
are constant constituents of all material atoms and molecules. 
Many chemists fail to coincide with the views of this eminent 
physicist, and few follow him to the extreme suggestion that 
these corpuscles constitute 4 negative electricity, which implies 
a return to the electric single fluid theory of Franklin. 

In 1894 Lenard, 5 acting upon a suggestion of Hertz, 6 
replaced a portion of the glass wall of the tube opposite the 

1. Compt. Rend. 121, 1130. 

2. Phil. Mag. V, 44, 293. 

3. Phil. Mag. V, 547 (1899) ; Proc. Roy. Inst. 16,574, (1901). 

*It has been calculated that the hydrogen atom weighs 2.3x10-21 

4. Harper's Magazine 103, 564, Sept. 1901. 

5. Ann. Phys. Chem. 51, 225 ; 56, 255, (1895). 

6. Prof. Hertz observed that a very thin metallic film interposed in- 
side a Crookes tubes permitted the grass to flouresce under cathodic bom- 
bardment. The aluminum foil quite opaque to light, did not prevent 
this flourescence of the glass behind it. 


cathode with a very thin plate of aluminum (Fig. 6) and thus 
led the cathode rays out of doors, as it were, under ordinary 
pressure. If the Lenard rays are not a prolongation of the 
cathode rays, they are closely identified with them, for they 
can be deflected by a magnet, excite luminescence, and they 
affect a photographic plate. While the air is a turbid medium 
for them, they readily pass through thin sheets of aluminum, 
or even copper, and discharge an electroscope enclosed in a 
metal box. L,enard explored his rays by using a small lumi- 
nescent paper screen covered with a wax -like organic chemi- 
cal, pentadecylparatolylketone. 


Fig. 6. 

Lenard's tube. B is joined to a vacuum pump ; A is anode ; C cath- 
ode ; Da thin aluminum window; From S. P. Thompson's "Light; 
Visible and Invisible." (Courtesy of the MacMillan Co.) 

A year later Rontgen, while investigating cathode rays 
as studied by Hertz and Lenard, discovered that something 
came from his tube which caused a barium platino-cyanide 
screen lying on the table to luminesce strongly. Rontgen's 
tube had a greater vacuum, no window (Fig. 7) and was 
covered by a shield of black cardboard. 1 The cathode rays, 
cannot pass through glass. The X-rays, he learned, possess 
remarkable penetrative powers, readily passing through paper, 
wood, hard rubber, tin and aluminum foil. Silver, copper, 
platinum, gold and lead were less and less transparent to them, 
a plate of the last named 1.5 centimetres thick being quite 
opaque. Rontgen found that his rays affected a photographic 

i. Uebereine neue Art von Strahlen (Vorlaufige Mitteilung), Sitzungs 
berichte der Wiirzburger physik. medic. Gesellschaft, 1895. Nature 53. 
274, (1896); Ann. Phys. Chem. 64, i, 12, 18, 91, 898. 


plate and that they differed from light rays, (visible, the ultra- 
violet, or infra-red, and any of those we have to consider), in 
not being reflected, refracted, or polarized. 

Although Rontgen's investigation was very complete, 
there was one observation he failed to make, which was noted 
by several workers, shortly after his modest announcement, 
namely, that Rontgen rays, like the cathode rays, possess the 

Fig. 7. 

Rontgen's first tube. C. is the cathode. (Courtesy of the MacMil- 
lan Co.) 

power of ionizing gases, when passed through them ; that is, 
dissociating them into ions and rendering them electric 
conductors. A charged electroscope (Fig. 8) may be readily 
discharged by the surrounding air made a conductor by the 
passage of X-rays through it. Ordinary flame will also ionize 

The effect upon a photographic plate gave a qualitative 
method for studying these rays, while the electrometric proce- 
dure presented a means of quantitative comparison. 

If the tube be too highly evacuated, no current passes 
through at all, a vacuum being a perfect insulator. The expla- 
nation of the Rontgen rays at present accepted is that they 
are produced without the tube as a result of the bombardment 
of the cathode rays within. By the use oan anti cathode, as 
shown in the modern Crookes tube, and by the automatic reg- 
ulation of the gas pressure within, the effect of the X-rays 
may be accentuated (Fig. 9). A larger surface of the glass 
fluoresces and phosphoresces. 

In an effort to learn the cause of the photographic effect 



and especially considering if it might be attributed to the 
glowing of the walls of the tube, Henry 1 found that it could be 

Fig. 8. 

An electroscope is an instrument which illustrates that like kinds of 
electricity repel each other. The illustration shows thin strips of metal 
attached to a rod passing through a cork in a bottle. When a charged 
body is brought near the knob the leaves within are charged hence di- 
verge. Anything which causes the air particles to become better conduc- 
tors of electricity than ordinarily, will cause the leaves to collapse. The 
rendering of gases, as the air, a better conductor is known as ioniza- 
tion. Fig. 8 shows an Aluminum leaf electroscope, covered with a wire 
netting and metalic cap, which prevent its discharge by ordinary elec- 
tric disturbances. The Rontgen rays discharge it whether charged by 
positive or negative electricity. 

Fig. 9. 

A modern Crookes tube for X-ray work. It is provided with a small 
side tube which contains a substance which absorbs or gives up sufficient 
gas to produce most penetrative effects. 

i. Compt. Rend 122, 384, (1896). 


augmented by phosphorescent zinc sulphide and Nieweng- 
lowski 1 observed that phosphorescing calcium sulphide would 
blacken a plate surrounded by light-tight paper. Troost 2 
made a similar observation with Sidot's blende, and naturally 
occurring hexagonal zinc sulphide. H. Becquerel 3 (Figs. 10 
and n) found that calcium sulphide, the variety which phos- 
phoresces blue-greeu to blue, would act strongly upon a photo- 
graphic plate through two m.rn. of aluminum foil, even though 
it were within a glass tube. W. Arnold 4 verified and extended 
these observations. The experiences of Madame Curie, Hof- 
mann and Z^rban, and ourselves did not accord with these 

As a result of a series of photographic experiments LeBon 5 
concluded that sunlight generates in all bodies upon which it 
falls rays of " black light." The rays are invisible to the 
eyes. Their existence is shown by their action on a gelatin- 
ized silver bromide plate. Lumiere, Becquerel and d'Arson- 
val 6 opposed this view and maintained that the black light is a 

Fig. 10. 

1. Coinpt. Rend. 122, 384, (1896). 

2. Compt. Rend. 122, 564, (1896). 
.3. Comp. Rend. 122, 559, (1899). 

4. Wied. Ann. 61, 316, (1897). 

5. Comp. Rend. 122, 188, (1896). 

6. Comp. Rend. 122, 500, (1896*. 



Fig. ii. 

These two foregoing figures present small glass exhibition tubes 
containing various phosphorescing substances resting upon an aluminum 
shield, 2 m. m. thick, which is separated from the sensitive film of the 
plate by black paper. The second figure is the plate after forty-eight 
hours exposure. The "light" from the calcium sulphide and hexagonal 
blende did not penetrate the shields. (From Becquerel's paper). 

kind of after light. They, also, put forward the idea that 
fluorescing substances, as for example the yellowish-green- 
glowing glass, are able to send out rays which penetrate dark 
bodies similarly to the Rontgen rays. 

Physicists have long known that the salts of uranium lum- 
inesce most beautifully in the sunlight. Becquerel 1 next 
directed his attention to the double uranium potassium sul- 
phate. This salt was placed on a plate so protected as to pre- 
vent the entrance of any sunlight. The whole was then 

i. Compt. Rend. 122, pp. 420, 501, 559, 689, 762, 1086, (1896); 
I2 3> 835. Also address before the Roy. Inst., Great Britain, March 7, 


exposed to the sun. On developing, the plate was found to 
be darkened. While preparing to repeat the experiment one 
day, it became cloudy. The whole apparatus was pliced in a 
dark drawer where it remained during several days of inclem- 
ent weather. For some unexplained reason the plate was 
developed without exposure to the sun at all. To his great 
surprise, he found that the plate had been distinctly affected. 
Becquerel's eminent father had shown years before that the 
phosphorescence of uranium salts persists but a very short time. 
Becquerel dissolved the double uranium potassium sulphate 
and purified it by recrystallization. The property of phos- 
phorescence is not evident in solution. The entire process 
was carried out in the dark... He repeated the experiment with 
the photographic plate, being careful not to allow any expo- 
sure of the apparatus or material to light. (Figs. 12 and 13). 
Similar results to those noted above were obtained. 

A number of uranium compounds were proved to possess 
this property (Fig. 14). The metal itself acted three and a 
half times as strong as the original sulphate. Further, while 
the light of the alkaline earth sulphides, zinc blende and other 
phosphorescing bodies gradually goes out in the dark, Bec- 
querel proved that the property of uranium preparations of 
giving out rays, which penetrate light tight media, did not di- 
minish even when they were kept for months in an abso- 
lutely dark place. 

Becquerel's statements as to the "uranium rays" were 
almost immediately verified and extended by Spies, 1 Elster and 
Geitel, 2 Miethe, 3 Kelvin, 4 Beattie and de Smolan, 5 and Ruther- 
ford. 6 . Later Hofmann and Strauss 7 and Crookes 8 , examined 

1. Verb, derphysik. Ges. Berlin 15, 102, (1896). 

2. Jahresber. Naturw. Braunschweig, 10, (1897). 

3. Intern, photogr. Monatsschrift f . Mediz. 4, 33, (1897' 

4. Nature 55, 344, 447, (1896). 

5. Phil. Mag. V, 43, 418 and 55, 277, (1897). 

6. Phil. Mag. V, 44, 422, (1897) and 47, 109, (1859). 

7. Ber. dtsch. Chem. Ges 33, 3126, (1900). 

8. Proc. Roy. Soc. 66, 406, (1900). 


Fig. 12. 

Early Radiograph of an aluminum medal made by Becquerel with 
an uranium salt. 

Fig. 13. 

North Carolina uraninite (gummite) acted through a glass upon the 
plate in ninety hours. 


Fig. 14. 

Radigraph made by J. Collier of Denver with a pitchblende^from 
the Wood mine of L,eaven worth gulch, Gilpin county, Colorado. It is 
interesting as showing the relative transparency and opaqueness of differ- 
ent substances to the radium and uranium radiation. In this case the 
plate was not wrapped but enclosed in double light proof box, which was 
set in a dark room. Weight of pitchblende 7^ ounces ; distance from 
plate, 4 inches ; radiating surface, i^ inches in diamater ; exposure two 
weeks. Key to objects ( i) house finch ; (2) imitation diamond ; (3) real 
diamond; (4) cameo; (5) quartz crystal; (6) and (7) fluorspar; (8) 
Kauri gum ; (9) tiger ej'e ; (10) turquoise ; (n) thick sheet lead ; (12) 
thin sheet lead ; (13) window glass ; (14) centipede ; (15) iceland spar ; 
(16) amber ; (17) black rubber.) By courtesy of the Western Miner and 
Financier. ) 

many of the uranium minerals, (pitchblende, uraninite, brog- 
gerite, cleveite, samarskite, and autunite, etc.), and found that 
they affected the photographic plate in the samejmanner. 
(Fig. 15). 

It may be recalled that Rontgen rays are able to pene- 
trate opaque sheets of metal, black paper, wood, caoutchouc, 
and so forth, and that they also have the property of ionizing 
gases. 1 The discovery showed that the Becquerel rays pos- 
sessed the same properties. (Fig. 16). 

i. Thomson and Rutherford, Phil. Mag. V, 42, 392, (1896). 


It is well known that the components of sunlight are re- 
frangible and capable of polarization by means of tourmaline 
or Nicol's prisms. Rutherford 5 showed that the uranium ray's 
possess this property in as limited a degree as the X-rays. This 
brilliant physicist, with Soddy, (i showed the complex nature of 
the rays. 

Those which are designated ,5- Rays have the following 
properties : 

They are penetrative and affect the photographic plate. 

They do not discharge the electroscope hence do not ionize 
gases and are but slightly absorbed by them. 

When subjected to the influence of the magnetic field, 
they are bent like the cathode rays. 

Fig. 15- 

Carnotite impressions or flashes made by H. H. Buckwalter. Plate 
inf double light-proof envelope. Time of exposure, one day. Nos. i 
and 2, carnotite concentrates, about seventy-five per cent, uranium from 
two per cent. ore. No. 3, very rich carnotite from the vicinity of Natu- 
rita, Colorado. (By courtesy of the Western Miner and Financier. 

4. Compt. Rend. 124,800, (1897). 

5 . Phil. Mag. 47, 109, (1899). 

6. Proc. Chem. Soc. 18, 121. 


Fig. 16. 

Radiograph made with Gilpin county (Colo.) pitchblende, by H. H. 
Buckwalter. Plate wrapped in two thicknesses of black paper. Time of 
exposure five days. About one-half pound of ore in two samples was 
used, separated from objects by a white pine board one inch thick. Dark 
circular object, an ordinary glass lens in chamois bag ; square object, an 
aluminum box containing washers. Rays at greater angle passing 
through greater thickness cause apparent shadow. ( By courtesy of the 

Western Miner and Financier. ) 

A i pH . 
The '2- rays act thus : 

They have no noticeable effect on the photographic plate. 

They are responsible for most of the ionizing effect of the 
uranium preparations and are readily absorbed by different 

They are unaffected by the magnet. 1 

These facts, first established by Rutherford and Soddy, 
were subsequently; recognized by Becquerel. (Fig. 17). 

This phase of the subject will be reverted to in a later 
chapter and we shall put aside its further discussion until 

i. This was later found to be incorrect, as will be shown. 



For the present, let us assume the novel fact that energy 
comes continuously from uranium and its compounds. This 
energy loses nothing in intensity, even on keeping the radiant 

Fig. 17. 

The figure illustrates the absorption power of the different rays pos- 
sessed by the screens of black paper, aluminum m. m., and platinum 
0.03 m. m. thick. The rays are deflected by a field about 1,740 C. G. S. 
units. The plate is unprotected except for the strips. The differences in 
penetration are readily noted. (After Bacquerel.) 

material in complete darkness for several years, as shown by 
Becquerel, and Elster and Geitel.. To be sure as Rutherford 
has shown, this energy is small 1 and apparently spontaneous, 
unaffected by _ temperature, 2 and unchanged in liquid air 
(-i 80 C). What is the cause of this unique physical phe- 
nomenon ? 

In 1897 Madame Sklodowska Curie of the Ecole Munici- 
pale de Physique et de Chimie Industrielle at Paris, began an 
investigation of the relative activity of the various salts of 
uranium and later minerals bearing that element. 3 She meas- 
ured the intensity of the radiation by its effect on the conduc- 
tivity of the air unit. The apparatus is here described in her 
own words : 

1. i g. of uranium oxide gives out in a year 0,032 Cal. of energy, 
Wied. Ann. Beibl. 24, 1,338, (1900). 

2. Rutherford, Phil. Mag. 47, 109, (1899) and Becquerel, Compt. 
Rend. 130, 1,584 and 131, 137. 

3. Compt. Rend. 126, i, 101, April, 1898. See also her exquisite thesis 
presented to the Faculte" des Sciences de Paris, which may te had in 
English for a small sum from the Chemical News of London, from which 
it has been reprinted. 


' ' The method employed consists in measuring the conduc- 
tivity acquired by air under the action of radio-active bodies ; 
this method possesses the advantage of being rapid and of fur- 
nishing figures which are comparable. The apparatus em- 
ployed by me for the purpose consists essentially of a plate 
condenser, A B (Fig. 18). The active body, finely powdered, 
is spread over the plate B, making the air between the plates 
a conductor. In order to measure the conductivity, the plate 
B is raised to a high potential by connecting it with one pole of 
a battery of small accumulators, P, of which the other pole is 
connected to earth. The plate A being maintained at the 
potential of the earth by the connection C D, an electric cur- 
rent is set up between the two plates. The potential of the 
plate A is recorded by an electrometer E. If the earth con- 
nection be broken at C, the plate A becomes charged, and this 
charge causes a deflection of the electrometer. The velocity 
of the deflection is proportional to the intensity of the current, 
and serves to measure the latter. 

' ' But a preferable method of measuring is that of compensa- 
ting the charge on plate A, so as to cause no deflection of the 
electrometer. The charges in question are extremely weak ; 
they may be compensated by means of a quartz electric 
balance, Q, one sheath of which is connected to plate A and 
the other to earth. The quartz laminae are subjected to a 
known tension, produced by placing weights in a plate. The 
tension is produced progressively and has the effect of genera- 
ting progressively a known quantity of electricity during the 
time observed. The operation can be so regulated that, at each 
instant there is compensation between the quantity of elec- 
tricity that traverses the condenser and that of the opposite 
kind furnished by the quartz. In this way the quantity of 
electricity passing through the condenser fora given time, z *., 
the intensity of the current, can be measured in absolute units. 
The measurement is independent of the sensitiveness of the 

"In carrying out a certain number of measurements of this 
kind, it is seen that radio-activity is a phenomenon capable of 




Fig. 18. 

Plan of apparatus used by Mme. Curie for measuring the intensity 
of radiation from active bodies by their effect on the conductivity of the 
air. (From her thesis.) 

being measured with a certain accuracy. It varies little with 
temperature ; it is scarcely affected by variations in the tem- 
perature of the surroundings ; it is not influenced by incandes- 
cence of the active substance. The intensity of the current 
which traverses the condenser increases with the surface 
of the plates. For a given condenser and a given substance the 
current increases with the difference of potential between the 
plates, with the pressure of the gas which fills the condenser, 
and with the distance of the plates, (provided this distance be 
not too great in comparison with the diameter). In every case, 
for great differences of potential the current attains a limiting 
value, which is practically constant. This is the current of sat- 
uration, or limiting current. " 

A discussion of the laws of conductivity of air and other 
gases subjected to the influences of the Rontgen and Bec- 
querel rays, cannot be incorporated in a work ef elementary 
character, so the reader is referred especially to the investiga- 
tions of J. J. Thomson and Rutherford. The mechanics of the 
phenomenon appear to be the same in both cases and the 
theory agrees well with the observed facts. However, accord- 
ing to Townsend, the phenomenon is more complex when the 
pressure of the gas is low. 


Using the term coined by the brilliant scientist, Madame 
Curie, the "radio-activity" of uranium and its compounds 
varied with the percentage of the metal present, as shown by 
Becquerel, hence the unique property was attributed to that 
element. Madame Curie verified the general conclusion, per- 
fected methods of measurements and greatly extended the 
range of observation with consequent alterations. (Fig. 19). 
She measured all the common metals and non-metals, many rare 
compounds, and a large number of rocks and minerals. She 
found no simple substance other than uranium and thorium 
which gave evidence of atomic radio-activity. G. C. Schmidt 1 
was the first to publish a statement as to the radio-activity of 
thorium. A striking fact is to be noted here. Thorium and 
uranium were the two elements then known to possess the 
highest atomic weights (232 and 240). 2 They frequently occur 
in the same minerals. 

C' C' 

Fig. 19. 

Electroscope used by Mme. Curie for qualitative examination of radio- 
active substances. The gold leaf I/ when electrified through the termi- 
nal at B is repelled from the fixed metal strip I,. Plate P, upon which 
the substance to be tested is placed, is connected with the metal case en- 
closing the apparatus. Plate P / is connected with the strips I, and I/. 

1. Wied. Ann. 65, 141, (1895). 

2. It should be noted that white phosphorus, undergoing oxidation, 
according to Black, causes the air to become a conductor. As neither the 
red variety nor compounds of phosphorus exhibit this property, it is readily 
attributed to chemical action and cannot come into consideration here. 


When the air between the plates becomes ionized a charge passes across- 
and I/ falls. By rating the time necessary for collapsing, or by having a 
scale at the back and rating the time required for the leaf to pass 
through a selected number of divisions, the radio-activity may be ap- 
proximately determined, e. -., that portion which ionizes gases. There 
are several forms of apparatus using the same principle. The limits of 
this book will not admit of their description, other than to call attention 
to Rutherford's variation, namely, the leaves are insulated from the rest 
of the apparatus being suspended by means of a sulphur bead. After 
charging through the conductor t ff , it is swung aside. "The rate of leakage 
is thus reduced to a minimum. 

The following is a table made by Madame Curie giving 
in io" 11 amperes the intensity of the current obtained with 
metallic uranium and with different minerals. 


Uranium %. . . . s. .. . . . . 2.3 

Pitchblende from Johanngeorgenstadt 8.3 

Pitchblende from Joachimsthal ... v . .....; 7.0 

Pitchblende from Pzibram . . 6.5 

Pitchblende from Cornwallis , . . . .1.6 

Cleveite 1.4 

Autunite : k . 2.7 

Chalcolite : . 5.2 


Various thorites ".- . . . .1.3 


Orangite 2.0 

Monazite 0.5 

Xenotime. . - 0.03 

Aeschynite o. 7 


Fergusonite (two samples) o. i 

Samarskite .....-'... I I 

Niobite (two samples) 03 

Tantalite 02 

Carnotite ..... 6.2 

All the minerals having radio-activity contained uranium 
and thorium. A glance at the table, however, shows the 
amazing fact that certain minerals possess a greater intensity 
than the metal uranium itself. This is utterly at variance 
with what we have already learned, namely, that the radio- 


activity is dependent upon the percentage of the metal, ura- 
nium or thorium, present. 

Afanasjew 1 examined fifty- one minerals by their action on 
a photographic plate. All the minerals containing uranium 
and thorium blackened the plate. Pisani 2 made somewhat 
similar experiments and raised the question, Is this astonish- 
ing state of affairs due to the small percentage of the oxides of 
uranium and thorium, or is it caused by the presence of a new 
radio-active body? 

To throw light on the subject, Madame Curie prepared 
artificial chalcolite, a double copper uranium phosphate, from 
pure materials. It showed normal activity, namely two-and-a- 
half less than uranium, instead of 5.2 as great. Pisani 's ques- 
tion was answered. Madame Curie's inevitable conclusion was. 
that pitchblende, chalcolite and autunite contained a small 
quantity of a strongly radio-active body, differing from uranium 
and thorium, differing from any of the elementary bodies 

The difficult problem which confronted this intrepid woman 
was the seeking of a new element, each faltering step being 
guided by a veritable fairy wand. The glorious outcome of her 
researches joined the century most replete with human achieve- 
ment to another, which promises even more and greater 

1. J. Russ. Phys. Chem. Soc. 32, ii, 103 (1900). 

2. Bull. Soc. franc. Mineral, 27, 58. 




Pitchblende is an expensive mineral mined mainly in Bohe- 
mia for the uranium it contains. It is one of the most com- 
plex ores ; containing besides the uranium, iron, calcium, lead, 
aluminum, silicon, copper, bismuth, zinc, cobalt, nickel, man- 
ganese, antimony, arsenic, vanadium, thallium, columbium, 
tantalum, many rare earths, and so forth. In the course of 
her search for the cause of the unique properties possessed by 
the uranium bearing minerals, Madame Curie 1 obtained a very 
radio-active substance, resembling bismuth, which she named, 
polonium, after her native country. This will be dealt with 
later. For this work she received the Gegner prize of 4,000 
francs. At this point her husband having joined in the work, 
they were assisted by M. Bemont, Director of the Ecole Muni- 
cipale. 2 Pitchblende, in sufficient amount, being beyond the 
purse of the teacher she secured from the Austrian Govern- 

1. Compt. Rend. 127, 175. Rapports au Congres International de 
Physique, III, 79, Paris (1900). 

2. Madame Sklodowska Curie was born in 1867, at Warsaw, Poland, 
where she received her early training. In 1891' she went to Paris, con- 
tinued her studies at the University and received her "Master's" degree 
in Physics and Mathematics. She married Professor Pierre Curie, the 
Professor of Physics at the University of Paris, in 1895. The year fol- 
lowing she successfully qualified as a candidate for a professorship in a 
girl's college. In 1900 she was appointed Professor of Physics in the 
State Normal School for Women at Sevres. She received her "Doctor's" 
degree recently for the thesis already quoted. The writer knows of no 
doctorate dissertation of such scope, elegance, breadth of conception and 
importance in its contribution to knowledge. 


ment a ton of the ' ' tailings ' ' or residues of the ores from which 
the uranium had been extracted. 

To extract the uranium, the process is as follows : The 
crude ore is crushed, roasted with sodium carbonate, washed 
with warm water and then with sulphuric acid. The solution 
contains the uranium. The insoluble residue, "tailings," 
which is rejected, contains most of the bodies of high radio- 
activity ; its activity being four and a-half times that of metallic 
uranium. Laboratory methods not being easily applied, M. 
Debierne organized the treatment in the factory, which was 
erected at Ivry without the walls of the city of Paris. 

A ton of the residues was worked up and a few decigrams 
of a substance resembling barium obtained. This was many 
thousand times as active as uranium. Although this substance 
showed but slight change in its atomic weight from that of 
barium, and no characteristic new lines were to be seen in the 
visible spectrum, according to Demarcay, it glowed feebly in 
the dark, affected a photographic plate through black paper 
and even thin sheets of metal, and ionized gases. These facts 
were sufficient to warrant the assumption of the presence of a 
new element. It was named radium. 1 

So far, although Phillips, 2 Bolt wood, 3 and others have pro- 
posed methods for analyzing ores for radium, it has not been 
extracted commercially in America. Lockwood, at Buffalo, 
has installed a plant for its extraction from carnotite, but as 
yet no preparations from that factory have been placed upon 
the market. 

The importance of the discovery of radium, the minute 
percentage in which it is found, the extremely unique proper- 
ties possessed by its compounds, the desire for it on the part of 
experimenters and even the merely curious, and its possible 
utility in medicine have created a radio- mania. The demand 

1. Compt. Rend. 127, 1215. 

2. American Phil. Academy, April Meeting, (1904). Science, May 6th. 

3. Bng. Min. J. May 12, (1904). 

Boltwood (Eng. & Min. Jour. 77, 756) tested for the presence of ra- 
dium in uranium compounds as follows : 


has been far in excess of the supply. The prices have almost 
tripled. The Austrian Government has forbidden the ship- 
ping of uranium ores or tailings without that country. Many 
tons of uranium ores have been shipped from the United 
States to Europe. The United States Geological Survey in 
seeking the locations of all the uranium bearing ores, has 
with its usual progressiveness appointed a special expert 1 and 
issued a letter on the subject. It says : 

"The simplest means of detecting radio-activity in a substance is 
by use of the photographic plate. The more sensitive the plate the 
better. The plate should not be removed from the enclosing black 
paper, and a metal object should be laid upon this black paper in a 
dark room; upon this should be placed the specimen to be tested. 
Instead of the metal object a few small nails may be arranged so as 


"A piece of apparatus (Fig. 21) constructed entirely 
of glass was first prepared. This consisted of a bulb (A) 
of about 50 cubic centimeters capacity, which was joined 
by a short tube to a smaller bulb (B). An accurately 
weighed quantity of the very finely powdered mineral 
was introduced into the bulb B, and in the bulb C was 
placed a sufficient quantity of a suitable acid, its actual 
quantity and nature depending on the character of the 
particular mineral under investigation. The whole ap- 
paratus was then sealed up air-tight at a slightly 
diminished pressure and, by tilting, the acid was trans- 
ferred to the bulb B, containing the mineral. The 
mineral was then completely decomposed by gentle 
warming and the apparatus was allowed to stand for 
several days to permit the radium emanation, which is 
D freed when the radium gaits pass into solution, to diffuse 
uniformly through the interior of the apparatus. The 
bulb A was then sealed off from the rest of the apparatus, 
allowed to stand for two hours, in order that any rapidly 
decaying emanations (actinium and thorium) which it 
contained might completely decompose, and, after wa- 
shing the interior walls with a strong sodium hydroxide 
solution to completely remove acid fumes, the air and 
radium emanation which it contained was transferred to an air-tight 
electroscope, and the rate of the leak measured." 

The sensitiveness of the method is extraordinary. Dr. Boltwood was 
able to compare the relative quantities of radium in two samples of 
pitchblende weighing from .001 to .002 gram. He was able to detect the 
presence of .000,000,000,1 gram of radium. It is probably possible to 
quantitatively estimate the quantity of radium equal to perhaps i-iooth of 
the above. 

Fig. 21 

i. Dr. Geo. F. Kunz, 40 East 25th St., New York City. 


' Fig. 2 1 a. 

Radium Exhibit of U. S. Geological Survey, Dr. G. F. Kunz, Special 
Agent, Louisiana Purchase Exposition, St. Louis, 'Mo., U. S. A. (By 
courtesy of the Survey.) 


to form the initial of the owner and left on the paper-covered plate 
below the specimen. The specimen should be left in the dark room 
from two to fifteen hours and then developed in the usual manner. If 
the specimen has radio-active powers, a photograph of the metal object 
or of the nail-formed initial will be produced on the plate exactly as if it 
had been exposed to the sun's rays. The test should be made, if 
possible, with from half a pound to a pound of the material. The 
electrical method is more reliable, but is much more difficult." 

M. Jacques Danne, 1 Preparator for Mine. Curie, says: 
"The extraction of the radium salts from pitchblende and car- 
notite takes place in three stages. The first stage consists in 
the roasting of the uranium ores, the preliminary roasting with- 
out soda, the final roasting with soda and a little saltpetre. The 
ores are then treated with sulphuric and a little nitric acid, and 
the resulting solution contains the uranium salts, while the 
radio-active metals are contained in finely divided form in the 
residue as sulphates. The residue is then treated with con- 
centrated hydrochloric acid and a part of it goes into solution. 
This solution contains the greater part of the elements polonium 
and actinium. Polonium is precipitated with sulphuretted 
hydrogen and in the filtrate the actinium is thrown down with 
ammonia after oxidation. The residue from the treatment with 
hydrochloric acid, which contains the radium, is washed with 
water and treated with concentrated boiling soda solution, in 
order to change the sulphates, which were left undecomposed 
by the treatment with hydrochloric acid, into carbonates. The 
residue is washed with water and digested with pure hydro- 
chloric acid. The solution resulting from this treatment con- 
tains radium and a little polonium and actinium. After filtra- 
tion the solution is treated with sulphuric acid, which throws 
down a mixture of sulphates of radio-active barium, lead, cal- 
cium, and a little actinium. One ton of uranium residues 
furnished about 10 to 20 kilograms of the mixtures of sul- 
phates, the radio-activity of which is 30 to 60 times greater than 
that of metallic uranium. The mixture of sulphates is treated 
with boiling concentrated soda solution, and the carbonates 

i. Genie Civil, Jan. 16 (1904). 


thus obtained are converted into chlorides by hydrochloric acid. 
Sulphuretted hydrogen is introduced into the solution, whereby 
a small precipitate of active sulphides which still contain the 
polonium is formed. The filtrate from this precipitate is then 
oxidized with potassium chlorate and precipitated with am- 
monia ; the hydrates and oxides thus precipitated still contain 
actinium. The filtrate is treated with soda to precipitate the 
carbonates of the alkaline earths, this precipitate being then 
converted into chlorides and the solution evaporated to dry- 
ness. The dry residue is treated with concentrated hydro- 
chloric acid, when the radio-active barium chloride and the 
radium chloride remain insoluble. This residue of chlorides 
is then dissolved in water, the carbonates precipitated by adding 
soda, and the precipitate treated with hydrobromic acid in 
order to convert the carbonates into bromides. A ton of ma- 
terial treated in this way furnishes about 8 to 10 kilograms of 
radio-active barium bromide nearly 60 times more radio-active 
than metallic uranium. The bromide is now subjected to a 
long series of crystallizations, 1 dependent upon the fact that the 
radium bromide is less soluble in water than the barium bro- 
mide. Each crystallization furnishes a product which has a 
greater radio-activity than the preceding and this treatment is 
kept up until the desired radio-activity is reached." 


The element radium has not yet been obtained. Wedekind 2 
and Marckwald 3 have, however, prepared radium amalgams; 
the former by electrolysing a halogen compound in the pres- 
ence of mercury, and the latter by treatment with sodium amal- 
gam. No description of the metal can be given and we do not 
know certain of its properties, as the specific gravity, melting 
point, etc. Curie says it is a mere matter of obtaining sufficient 
of the chloride, when it may be prepared like the alkaline earth 

1. As first suggested and done by Giesel. 

2. Chem. Zeit. 28, 269 (1904). 

3. Berichte, Chem. News, 89, 97. 


metals. The difficulty of working with large quantities are very 
apparent when we realize that only a few centigrams of fairly 
pure material are had from two tons of the ore, and are aware 
of certain properties soon to be mentioned. 

The chloride, bromide, carbonate, acetate, nitrate, and sul- 
phate of radium freshly prepared resemble similar salts of 
barium. The nitrates of radium and of barium are about 
equally soluble in water. The halides are isomorphous, but 
differ slightly in their solubility in water. 

Radium salts gradually assume color. Apparently they 
undergo alterations through the influence of the rays they emit, 
giving out oxygenated chlorine compounds, if the salt be a 
chloride. Giesel has shown that a water solution of a radium 
salt gives off hydrogen continuously. 

The earlier prepared compounds of radium were much 
contaminated with barium and gave an atomic weight of 137.5. 
barium being 137.35. Successive fractionations gave 146,* I75, 2 
and finally 225. 8 

In order that a new substance may claim a place in the 
family of chemical elements, it has been agreed that it must 
give a characteristic spark spectrum. A preparation not very 
strong was submitted to Demarcay, 4 who found in addition to 
the barium lines," a new one in the ultra-violet. With purer 
materials that lamented chemist photographed a characteristic 
spectrum, which is in general similar to the alkaline earths. 
With radium bromide prepared by Giesel, Runge 5 and Precht, 
Exher and Haschek 6 obtained the spark and flame spectra of 
the characteristic carmine-red coloration given by the Bunsen 
flame. Their work was concerned largely with* the visible 

1. Compt. Rend. 129, 20. 

2. Compt. Rend. 131, 6. 

3 Compt. Rend. 135, 161 (1902). 

4- Compt. Rend. 127, 1218 (1898) ; 129, 716 (1899) ; 131, 258 (1900). 

5. Astrophys. Journ. i (1900). 

6. Sitz. Ak. Wiss. Wien. July (1901). 


spectrum, while Demargay observed the ultra-violet in the main. 
Recently Crookes 1 made an elaborate and extended study of the 
spark spectrum in the ultra-violet region. Runge and Precht 2 
noted the influence of a magnetic field on the spectrum and that 
it was composed of series analogous to calcium, strontium, and 
barium. As these series appeared to be connected with the 
atomic weights, they calculated that the atomic weight of 
radium should be 258. By utilizing the relation between the 
spectra of some elements, and the squares of their atomic 
weights, Watts 3 arrived at the same value given by Mme. Curie. 
Although Runge and Precht 4 have criticized, perhaps justly, 
the method used by Marshall Watts, the value 225 is accepted 
for several reasons, one being that that value causes it to fall in 
the family of alkaline earths in the periodic system of Mendele- 

A radium compound, within a closed glass tube, when 
brought near a screen of zinc sulphide, or barium-platino- 
cyanide, causes it to glow brightly in a dark room. Photo- 
graphic plates, covered with black paper, are at once affected. 

Fig. 22. 

Radium bromide within a closed glass tube affects the photographic 
plate through black paper. Pacini in our laboratory used the radium 
tubes as a pencil and traced the above. 

i. Sitz. Kgl. Pr. Akad. Wiss Berlin (1904), 417. 

2; Phil. Mag. April (1903). 

3. Phil. Mag. IV, 5, 203 (1903)- 

4- Phil. Mag. IV, 5, 476 (1903)- 


(Fig. 22.) All the radium compounds, so far obtained, are 
luminous in the dark. We do not know whether radium itself 
actually gives out luminous rays or whether the luminosity 
results from the conversion by the solid substance itself, or the 
impurities present, of invisible rays into those which give the 
effect of light on the optical organs. The presence of radium 
causes certain substances, as Thuringian glass, diamonds, wille- 
mite, kunzite, etc., to fluoresce and phosphoresce. 

The salts of radium appear to be a source of spontaneous 
and continuous evolution of heat. Curie and Laborde 1 first 
showed that the temperature of an impure radium salt is 1.5 C. 

Fig. 23. 

Simple method for illustrating the continuous disengagement of 
heat by radium. Delicate thermometers (t and t 7 ) in "duplicate are 
placed within calorifically isolated vessels (Dewar bulbs), A and A 7 . 
Small tubes of equal size, a and a 7 , containing molecular weights of, say, 
radium and barium chlorides, the latter being inactive, are inserted after 
thermic equilibrium has been established. ' (After Curie, see Danne.) 

i. Compt. Rend. 136, 673 (1903). 


Fig. 24. 

The quantity of heat given out by a radium salt has been deter- 
mined by the apparatus of Dewar and Curie, shown above. A small 
thin-walled Dewar bulb, A, containing liquid hydrogen, is immersied in 
liquid hydrogen, H'. within a larger thermic insulator, B. Tube H by 
means of glass tubing ends underneath the eudiometer, E, over water. 
No gas escapes through the exit tube, t, until the tiny glass vessel 
containing the radium compound is inserted, after whjch there is a con- 
tinuous and regular ebullition. 0.7 gram of radium bromide causes 
70 c.c. of hydrogen to be evolved every minute. Freshly prepared salts 
disengage relatively smaller amounts of heat. 

higher than the surrounding medium (Fig. 23). Later Curie 1 
found 3 and Giesel 5 C. difference for the bromide. The 
former, also, learned that the rate of the emission of heat 
depended upon the age of the compound. When the compound 
is freshly prepared the emission is small. It increases and 
reaches a constant maximum in a month. He also learned that 
if the salt be dissolved in water and placed in a sealed tube, that 
the difference in condition made no difference in the emission 
of heat. By the use of a Bunsen calorimeter, or the other 
method shown in the illustration (Fig. 24), Curie and Laborde 
learned that one gram of a pure radium salt emits about 100 
gram-calories of heat per hour. Runge and Precht 2 with others 

1. Societe de Physique. (1903). 

2. Sitz. Ak. Wiss. Berlin, (1903). 


Fig. 25. 

Skiagraph of tools made with radium bromide, 300,000 activity. 
Eight inches separated the plate and tube. Exposure forty minutes. 


Fig. 26. 

Showing penetration of radium rays. A lead bar was placed be- 
neath plates of cast iron ^ inch thick (Brown). 



Fig. 27. 

Illustrating the penetrability to radiations of radium of Aluminum 
(A), Micro-cover (B), Micro-slide (C), Red flash-glass (D), and a Silver 
Quarter (in the center). 

confirmed this continuous emission of heat. One gram of 
radium emits in a day 2400, or in a year 876,000 gram-calories. 
The radiations given out in part penetrate paper, thin 
metals, thick metals, glass, mica, etc. This wonderful phenom- 
enon has been studied by Strutt, 1 the Curies, 2 and others. Most 
striking experiments, illustrating the penetration of the rays, 
are easily performed. (Figs. 25, 26 and 27.) Hammer 3 placed 
a tube of 7000 activity within a cannon ball, sealed it, and 

1. Nature, 39, (1900). 

2. Loc., Cit. 

3. Radium and other Radio-active Substances, Lecture before the 
S. E. E. & Am. El. Ch. Soc., April (1903)- 



made a skiagraph. Kunz and the writer 1 caused a large tifrany- 
ite diamond to glow when radium bromide (300,000 activity) 
was protected by covers of glass, gutta-percha, steel tubing, 
three sheets of copper, one m.m. of silver and ten c.m. of water. 
Radium compounds are the first chemical preparations 
^) known to spontaneously charge themselves with electricity. 
Placed near electrically charged and isolated bodies, as an elec- 
troscope, they discharge them. (Fig. 28.) Thus they ionize 
gases, which property serves as a most delicate means of deter- 
mining in part the activity quantitatively. 2 (Fig. 29.) 

HH ihi 

Fig. 28. 

This figure illustrates a beautiful experiment of Professor Curie's, 
which shews the conductivity of the air under-the influence of radium. 
The secondary terminals, P P / , of an induction coil, B, are connected 
by wires with two sets of electrodes, M and M', so separated as to offer 
two paths for discharging sparks. If a tube of radium be brought near 
one- set, while the sparks are passing rapidly between both pairs, the 
sparks will cease at the second set as the path offered, where the 
radium is present, is much less resistant than the normal air at the 

1. Science. N. S. 18, 769, (1903). 

2. The term "ionization," as here used, has no reference to the 
modern theory of solutions, but to the interpretation given by J. J. 



Fig. 29. 

The apparatus used by the Curies for the determination of 
electrical conductivity is described in the words Madame Curie 
as follows : 

"The two plates of a condenser, P P and P' P' (Fig. 29), are hori- 
zontally disposed in a metallic box, B B B B, connected to earth. The 
active body, A, placed in a thick metallic box, C C C C, connected with 
the plate P' P', acts upon the air of the condenser across a metallic sheet, 
T; the rays which pass through the sheet are alone utilized for pro- 
ducing the current, the electric field being limited by the sheet. The 
distance, A T, of the active body from the sheet may be varied. The 
field between the plates is established by means of a battery. By placing 
in A upon the active body different screens, and by adjusting the dis- 
tance A T; the absorption of rays which travel long or short distances 
in the air may be determined." 

Attention must be directed at this point to an interesting 
phase of the investigation of these radio-active bodies. Coppel 1 
has determined that by means of the spark spectrum one 
may detect i part in 900,000 of barium and I in 100,000,000 
of strontium. The principal line of radium in the ultra- 
violet may be seen faintly in a preparation 40 times as active 
as uranium. By the electrical method, depending upon the 
ionization of the air, the presence of radium in a sub- 

T. Pogg. Ann. 628, (1870). 


stance may be detected when it possesses only i/iooo the activ- 
ity of uranium. With the most sensitive electrometer 1/10,000 
the activity of uranium may be observed. Thus we see that 
radio-activity is a detectable property nearly a million times 
more sensitive than spectrum analysis, which is at least a 
thousand times more sensitive than the most delicate balance. 
This should not excite great surprise. Berthelot 1 has called 
attention to a comparison of the delicacy of detecting radio- 
activity and odors, i/ioo billionth of a gram of iodoform is 
readily detected by a sensitive nose. 

Crookes 2 separated from uranium and the writer from 
thorium 3 ' a fraction which did not affect the photographic plate. 
Rutherford 4 showed that this portion, which did not affect the 
sensitive gelatine, continued to ionize gases. In short, the 
radiations were proved to be complex. (Fig. 30.) 

As a result of numerous investigations, by different work- 
ers, but mainly Rutherford, the radiations from radium have 
been found to consist of three types of rays : 

1. Those which are easily absorbed (a- rays) ; 

2. Those which are penetrating (/?-rays) ; 

3. Those which are very penetrating (y-rays). 

Rutherford 5 found, both in uranium and thorium, rays 
which differed -in their penetrating powers. He designated 
them a- and (3- rays. Later the very penetrating rays were 
obtained from these two elements and radium and designated 
y-rays. The term "ray" is applied to a stream of corpuscles, 
such as Newton pictures in his theory of light. 

The a- rays correspond to the canal rays of Goldstein 
which, according to Wien, consist of positively charged parti- 
cles, projected with great velocity. The /8-rays are the same 
as the cathode rays, while the y-rays, in .some respects, resem- 

1. Compt Rend. 138, 1249. 

2. Proc. Roy. Soc., 66, 409. ' 

3. J. Am. Chem. Soc. 23, 761. (1901). 

4. Phila. Mag. (1901). . 
5- Phil. Mag, Jan. (1899). 



Fig. 30. 

Radiograph of a fish obtained by an exposure of 40 minutes with 
radium of 300,000 activity. The lack of definition is noticeable, as the 
/3-rays were not separated. The lower of the two pictures is a radiograph 
of the same fish made by the Roentgen rays. 

ble the Rontgen rays. The Rontgen rays result from the ex- 
penditure of electric energy within a vacuum tube. They vary 
with the conditions, whereas those given out by radio-active 
bodies are apparently emitted spontaneously and at a rate not 
influenced by any chemical or physical agencies. The velocity 
and penetrating powers of the rays from radio-active bodies 
appear to be greater than those produced in a vacuum tube. 
The method used by Madame Curie for illustrating these rays 
is shown in Fig. 32. 

The ionization 'effect of the a-, /?- and y-rays is in the 
order 10,000 : 100 : i. The penetrating power of the rays 


is as follows : A sheet of aluminum 0.0005 c - m - thick will cut 
off one- half of the a- rays : 0.05 c. m., one-half of the /3-rays, 
and 8 c. m., one-half of the y-rays ; or, in short, it will be noted 
that ionization and penetration powers bear an approximately 
inverse ratio. The making of comparative measurements is 
fraught with numerous difficulties, so the figures are only 

For reasons that will become apparent, these rays will be 
considered in the order of their conduct under the influence of 
a magnetic or electro-magnetic field. 1 


Elster and Geitel observed that the conductivity produced 
in the air by radium rays was affected by a magnetic field. 
Giesel 2 demonstrated that the rays deviate under the influence 
of an electro-magnet in the same direction and in the same 
order of magnitude as the cathode rays. Meyer and von 
Schweidler 3 verified this later and Becquerel, 4 using the photo- 
graphic method, demonstrated the magnetic deflection of the 
rays. (Fig. 31.) Rutherford 5 demonstrated that the rays from 
uranium consisted of a- and /3-rays. 

P. Curie, by the electrical method, showed that radium 
rays consisted of non-deviable and easily absorbed (a- rays) 
and penetrating, but deviable by the magnetic field, (/?-rays). 
Rutherford and Grier, also using the electrical method, demon- 
strated that thorium compounds gave in addition to the a-rays 
some penetrating ft- rays, deviable in the magnetic field as in 
the case of uranium. The iqnization produced by the a-rays 
is large in comparison to that due to the (3-ra.ys. 

1. For a complete discussion of the methods of measuring ioniz- 
ation of gases the reader is referred to special works like J. J. Thom- 
son's "Conduction of Electricity Through Gases," and Rutherford's 

2. Wied. Annal. 69, 831, (1899). 

3. Phys. Zeit. I, 90, 113, (1899). 

4. C. R. 129, 997, 1205, (1899). 

5. Phil. Mag., Jan. (1899). 

6. Phil. Mag., Sept. (1902). 



-Fig. 31. 

The radium preparation is placed in a small lead cup open above. 
The rays are projected like the smoke from a mortar. Under the in- 
fluence of a powerful magnet or electro-magnet a portion are attracted, 
a portion repelled, and the remainder, being unaffected, continue in a 
straight line. (After Curie.) See next figure for a more graphic illus- 
tration and the nomenclature of the rays. 

Fig. 32. 

A graphic illustration of the radiations of radium. The active 
preparation (R) is in a lead cup. See description in the text. 



The ease with which the p-rays were deviated by the mag- 
netic, or electro-magnetic field and their penetration natu- 
rally commanded the greater attention at first. A magnetic 
field strong enough to produce a marked deviation of the 
yS-rays, had little or no effect upon the a- rays. In fact they 
were regarded as secondary rays, set up by the /3-rays in the 
active matter from which they were produced. It was learned, 
as adverted to, that the matter giving rise to the /?-rays could 
be separated from uranium, while the intensity of the a-rays 
was not affected. Strutt 1 and later Crookes* suggested that 
the a-rays might consist of positively charged bodies projected 
with great velocity. Madame Curie, 3 from her study of 
polonium, suggested the probability that these rays were bodies 
moving very rapidly, but losing their energy when they passed 
through matter. Rutherford 4 learned, by most careful experi- 
mentation with the electrical method, that the a-rays could be 
deflected by an intense magnetic field and in the opposite direc- 
tion from the cathode rays, and demonstrated that they con- 
sisted of positively charged particles. 

Becquerel 3 confirmed this by the photographic method. 
The naked radium preparation was covered with a metallic 
screen over a narrow slit. The photographic plate was placed 
two c.m. above this slit. The strength of the magnetic field 
was great enough to deflect all the /3-rays. The plate was 
affected not only immediately opposite the slit, but also on the 
side away from the magnetic field. On reversing the field for 
equal lengths of time the image, which had been produced by 
the a-rays, was observed to be reversed also. " Descoudres 6 

1. Phil. Trans. 507, (1901). 

2. Chem. News 85, 109, (1902). 

3. C. R. 130, 76, (1900). 

4. Phys. Zeit. 4, 235, (1902). 
5 C. R. 136, 199, (1903)- 

6. Phys. Zeit. 4, 483, (1903). 


proved that the a-rays of polonium are deviated in the same 


Wien has shown that the velocity of the projection of the 
canal rays varies with the gas in the tube and the intensity of 
the electric field applied. It is generally about one-tenth of the 
velocity of the a-rays from radium. For the a-rays of radium 
it has been shown that v = 2.5 X io 9 and e/m = 6 X io 3 , 
io 4 is the value of e/m for the hydrogen atom liberated in the 
electrolysis of water. If the charge of the a particle be the 
same as that of the hydrogen atom, the mass of the a particle 
is about twice as great as that of the hydrogen, which would 
indicate that it consists of either helium or hydrogen. This 
phase of the subject will be taken up in the fourth chapter. 

The a-rays, coming from different sources, vary in the 
amount of their absorption. About ninety-nine per cent, of 
the ionization of the air produced by naked radium is due to 
the a-rays 1 . The order of the penetration of the a-emanations 
as found is: thorium and radium (excited radiation), thorium, 
radium, polonium and uranium. The substances used were : 
aluminum, Dutch metal, paper ; air and other gases. 


Villard 2 and subsequently Becquerel 3 discovered by using 
the photographic method these very penetrating rays, which are 
non-deviable by a magnetic field. Rutherford, 4 by using the 
electroscope of C. T. R. Wilson, 5 found that uranium and thor- 
ium also gave out y-rays. 

T. Rutherford, Phil. Mag., Jan. (1899). 

Owens, Phil. Mag. Oct. (1899). 

Rutherford and Brookes, Phil. Mag. July, (1902). 
2. C. R. 130, 1 1 io, 1178, (1900). 
3- C. R. 130, 1154, (1900). 
4' Phys. Zeit. pp. 517, (1902). 
5. Proc. Roy. Soc. 68, 152, (1901). 


As a result of the investigations of Benoist, 1 Strutt, 2 and 
others, it is known that the y-rays possess great penetrating 
power ; that they are non-deviable in an intense magnetic field ; 
that y-rays and /3-rays occur together and in the same propor- 
tion ; that thev seem to be absorbed in a similar way to the 


The figure illustrates the method for obtaining sharp radiographs 
at variable distances, with salts of radium. The ordinary radiographs 
made by radium are poorly defined on account of the diffusion of the 
/3-rays. The tf-rays are absorbed by the container. The /?-rays are got 
rid of through the influence of a powerful electro-magnet. The radium 
compound, R, therefore acts like a minute but powerful Crookes tube 
evolving Roentgen rays, which produce a skiagraph of T:he object, O, 
on the plate, P protected by black paper. The y-rays from a small 
amount of radium may be caused to radiograph at variable distances, 
a meter or more, the time of exposure being much greater the farther 
apart are the plate and the source of energy. 

1. C. R. 132, 545, (1901). 

2. Proc. Roy. Soc. 72, 208, (1903). 


cathode and /3-rays ; and that active products, giving off a- rays 
and not /3-rays, do not produce y-rays. They appear to be 
very similar to the Rontgen rays that are produced in very 
"hard" tubes. 

Radium preparations brought near other substances pos- 
sess the power of inducing a secondary activity which dimin- 
ishes at various rates. They do not appear to lose weight. 
Such conduct apparently questions the fundamental laws of 
physics and chemistry, namely the conservation of mass and 
energy. This will be dealt with in the fourth chapter. 

Black 1 has shown that the electric resistance of selenium 
is diminished under the influence of radium rays. The action, 
though slower than in case of Rontgen rays, is of the same 
order of magnitude, as shown by Perrin. Van Aubel 2 has also 
shown that the electric conductivity of selenium is similarly 
affected in the neighborhood of hydrogen and oil of turpentine. 
Paillat 3 has called attention to the influence the radium rays 
have upon the electrical resistance of bismuth. 

Gases subjected to the influence of radio-active substances, 
according to de Hemptinne, 4 became luminous under electric 
discharges or higher pressures than normal conditions. There 
is a similarity, although a difference, between the Rontgen and 
Becquerel rays, the red-violet color of the gas in the former 
becoming yellowish-green under the influence of radio-active 


Radium preparations produce colors in glass, porcelain, 
rock salt, sylvite, etc. They have a destructive action on the 
skin ( See Chapter V ) . Becquerel 5 converted yellow phos- 
sphorus into the red variety through the influence of the /3-rays, 

1. C. R. 132, 15- - 

2. C. R. 136, 929. 

3. C. R. 138, 139- 

A. C. R. 133, 93- 1 , (1901)- 
5. C. R. 133, 709, (1901)- 


He, also, learned that mercuric chloride is reduced by oxalic 
acid when the mixed solutions are left in the dark with a radium 
tube. The germinating power of seeds is destroyed by an 
ante-planting exposure to the radiations. 

Radium converts oxygen into ozone, 'apparently through 
the influence of the a- and j3- and not the luminous rays. 

Berthelot 2 in making a comparative study of specific chemi- 
cal reactions caused by light, an electric current and radium, 
learned that, under the influence of the last named, iodic acid 
was decomposed, yielding free iodine. This did not occur when 
the radium was covered with black paper. Pure nitric acid 
was discolored at the end of a two days' exposure. These re- 
actions are endo- thermic. Light caused the decomposition of 
carbon disulphide. Acetylene is readily polymerized by an 
electric current. Radium brought about neither of these 
exothermic reactions. Lead glass was turned black, manganese 
glass violet, hence the radiations were supposed to cause a re- 
duction and oxidation simultaneously. However, later Ackroyd 3 
showed that the color changes, as orange for sodium chloride, 
violet for potassium chloride, etc., produced by the y-rays, cor- 
responded to thermal effects in other bodies and are physical. 

Mercurous sulphate, which darkens under the influence 
of ordinary light, especially the ultra-violet rays, is similarly 
affected by radium compounds. 4 The effect on the E. M. F. 
of a Clark cell is negligible, however. 

Sudborough 5 has shown that certain labile stereoisomer- 
ides, as allo-cinnamic, a- and /3-bromo-allo-cinnamic acids are 
transformed into stable compounds more readily under the in- 

1. Curies, C. R. 129, 823, (1899). 

2. Compt. Rend. 133, 18. Ann. Chem. Phys. (7), 25, 458, (1902). 

3. "The Action of Radium Rays on the Halides of the Alkali Metals 
and Analogous Effects produced by Heat." Proc. Chem. S. 20, 108, 

4. Skinner, "Action of Radium Rays on Mercurous Salts," Proc. 
Camb. Phil. Soc. 12, 260, (1904). 

5. Proc. C. S. 20, 1 66, (1904). 


fluence of light than by prolonged exposure to radium radia- 

Orloff 1 found that radio-active protuberances grew upon 
an aluminum plate exposed for three months above radium 
bromide in an ebonite capsule. He explained the phenomenon 
by the formation of a 'stable alloy with the accumulated ma- 
terial particles given off by the radium preparations. 

Hardy and Willcock z found that a solution of iodoform in 
chloroform turned deep purple by resting the containing vessel 
on a sheet of mica covering radium bromide. The liberation 
of iodine from solutions of iodoform has been found to require 
oxygen and some form of radiant energy. The action was 
found to be due mainly to the /3-rays, although the y-rays pro- 
duced the same effect. Rontgen rays produce a similar colora- 

Hardy exposed two solutions of globulin from ox-serum 
to the action of naked radium bromide. One solution was ren-, 
dered electro-positive, by adding acetic acid; the other nega- 
tive, by ammonia. The opalescence of the electro-positive prep- 
aration rapidly diminished, showing a more complete solution ; 
while the electro-negative rapidly turned to a jelly and became 
opaque. This coagulation of globulin was found to be due 
to the a- rays alone. 

This unique substance, it has thus been seen, possesses 
properties that are most amazing. Although the trail has been 
followed close by many drawn to a contemplation of the won- 
der, it is safe to say that we perhaps are only on the threshold 
of a full knowledge of this marvel. 

1. Russ. Phys. Chem. Soc., April (1903). 

2. Proc. Roy. Soc. 72, 200, (1903) ; Zeit. Phys. Chem. 47, 347. 





Becquerel 1 in his early studies of the invisible radiations 
emitted by salts of uranium attributed the darkening of the 
photographic plate to invisible phosphorescence. It did not 
seem to have any intimate association with visible phosphores- 
cence or fluorescence. The sesqui-salts are fluorescent, while 
the uranous or green salts are not, yet the radiations from the 
latter were as intense as the former. 

He 2 found that all uranium salts, as well as the metal, gave 
off invisible rays which penetrate gold, platinum and copper, 
black paper and affect a photographic plate. 

Becquerel 3 also learned that the radiations from uranium 
and its compounds showed no appreciable variation after three 
years. The rays were absorbed in proportion to the thickness 
of any material they passed through. All the uranium rays 
deviate under the influence of an electro-magnet. They resem- 
ble Rontgen rays more than ordinary light. The radiating sub- 
stances seem to be analogous to ordinary phosphorescent ma- 
terials, but to retain relatively a very much greater reserve of 

Becquerel, 4 in an effort to concentrate the active body in 
uranium, treated its salts with barium chloride, and subse- 
quently precipitated the latter by sulphuric acid. The precipi- 

1. Compt. Rend. 122, 689 and 762. 

2. Compt. Rend. 122, 1086. 

3. Compt. Rend. 128, 771 (1899). 

4. Compt. Rend. 131, 137 (1900). 


tate carried with it a radio-active substance emitting rays 
deviated by a* magnetic field. On repeating the operation 
eighteen times it was learned that the purified uranium pos- 
sessed only one-sixth its original ability of ionizing air. Its 
rays passed more readily through glass than aluminum, whereas 
the converse was true for the original salt. 

Crookes 1 learned that pure uranium nitrate fractioned with 
ether gave an inactive product (to the photographic plate), 
soluble in ether, while the activity became concentrated in the 
insoluble portion. He designated the active substance, pro- 
visionally, Ur-X. It differs from polonium, whose emanations 
do not pass through glass, aluminum or lead. It differs from 
radium in forming a readily soluble sulphate. 

Becquerel 2 supposed uranium to contain a highly active 
body, probably actinium, as a strongly radiating body could be 
concentrated by adding a small portion of a soluble barium salt 
and precipitating with sulphuric acid. Yet the extreme prod- 
ucts of a long series of fractionations of uranium nitrate by 
deBoisbaudran showed the same radio-activity, measured by 
the photographic and electrical discharge methods. 

Becquerel 3 found that the temperature of liquid air, reduced 
the discharging power of uranium, determined by a very deli- 
cate electroscope, to about one-half of that noted at 25 C. 
Crystals of uranium nitrate plunged into liquid air or hydrogen 
became spontaneously luminous. 

He 4 furthermore proved that the radio-activity of uranium 
was not constant, as Giesel had previously noted. 

Soddy 3 repeated the work of Crookes. He directed atten- 
tion to the fact, that by the photographic method, when the rays 

1. Proc. Roy. Soc. 66, 409 (1900). 

2. Compt. Rend, 130, 1583 (1900). 

3. Compt. Rend. 133, 4 (1901). 

4. Compt. Rend, 133, Dec. 9 (1901). 

5. Chem. News 86, 199 (1902). 


are made to pass through cardboard or glass before reaching 
the sensitive film, only the y- radiation will be measured, there- 
fore the a-radiation was left intact. 

Rutherford 1 showed that the radiation from uranium was 
complex, the (3- radiation being far more penetrating in charac- 
ter than the a-radiation. The difficulty of making an accurate 
determination is due to the small conductivity produced by the 
/3-radiation in the gas, as compared to that due to the a-radia- 


In 1898 G. C. Schmidt' 2 and Madame Curie' independently 
noted the radio-activity of thorium obtained from Bohemian 
pitchblende. Not long after the announcement of the Becque- 
rel 4 rays, Crookes, 5 as noted above, showed that by fractioning 
uranium nitrate with efher, compounds could be obtained which 
did not affect the photo-graphic plate. This indicated the sep- 
aration of a new substance (Uranium X) and that radio- activ- 
ity was not an inherent property of the element uranium, as 
maintained by Madame Curie. 

Soddy and Rutherford 7 demonstrated that only material 
carrying the /8-rays was thus separated and that the inactive 
uranium (so called because it does not affect the photographic 
plate) still gives off a- rays, which ionize gases and may be 
detected by the ejectrical method. Crookes, in the same paper, 
reported a few preliminary experiments on thorium compounds 
and suggested "the possibility of separating thorium from its 
radio-active substance." 

Hofmann and Zerban 8 found that the activity of thorium 
could be fractioned away. The activity is increased in that 

1. Phil. Mag. Jan., 1897. 

2. Wied. Ann. 65, 141. 

3. Madame Curie's Thesis, Faculte des Sciences de Paris (1903). 

4. Compt. Rend. 122, 420, 501, 559, 689, 762', 1086 (1896). 

5. Proc. Roy. Soc. 66, 406 (1900). 

6. Compt. Rend, 127, 175. 

7. Proc. Chem. Soc. 18, 121. 

8. Ber. d. chem. Ges. 35, 531 (1902). 


portion most readily precipitated by potassium sulphate, chro- 
mate, hydrogen dioxide, and sodium thio-sulphate. With am- 
monium carbonate the more active portion passes into solution 
They also examined a number of minerals from which thorium 
is obtained and proved the presence therein of uranium The 
thorium oxides from all of these were radio-active. Norwegian 
gadolmite, orthite and yttrotitanite free from uranium gave 
a thorium oxide which neither affected the electroscope nor the 
photographic plate. 1 

Fig- 3-1- 

This illustration shows on the left the action of a strong radio- 
active thorium preparation acting through i m.m. of glass upon a plate ; 
on the right the same preparation was placed, a half year later, black 
paper only protecting the powder from the plate. The loss of the in- 
duced (?) activity, or at least that portion affecting a silver-bromide 
gelatine preparation is very noticeable. The exposure was for twenty- 
four hours in both cases (After Zerban.) 

I. Ber. d. Chem. Ges 35, 533 and 145 (1902). 


The work of Hofmann and Zerban touching the primary 
activity of thorium being questioned by Barker, 1 was upheld 
by the junior author who detected the presence of uranium in 

The elegant researches of Rutherford and Soddy 2 proved 
that there can be no doubt of the existence of a novel highly 
radio-active substance with thorium (thorium X), as it is 
usually extracted from minerals without consideration of their 
chemical composition. Hofmann and Zerban strenuously direct 
attention to this last fact. Such prepared so-called pure salts 
of thorium contain a radio-active constituent, which may be 
concentrated chemically by precipitation with ammonia (the 
filtrate carries thorium X) 3 and washing the oxide with acid or 
even water. The residues obtained by evaporation of the am- 
moniacal solution in the first case are a thousand times as active 
as the original and "are free from thorium, or, at most, contain 
only the merest traces, and when redissolved in nitric acid do 
not appear to give any characteristic reaction." The residue 
from the water washings became 1,800 times as active, and after 
conversion into sulphate, Rutherford and Soddy state, "No 
other substance than thorium could be detected by chemical 
analysis, although, of course, the quantity was too small for a 
minute examination" 4 (See Emanium). 

Giesel' said the radio-activity of thorium could not be due 
to actinium. 

When we Consider that barium chloride containing radium 
may be precipitated by sulphuric acid or silver nitrate and the 
filtrate or precipitate obtained thereby, supposedly containing 
none of that remarkable body, is still radio-active, 15 we can easily 

1. "The Radioactivity of Thorium Minerals," Am. J. Sci. 16, 164 


2. Proc. Chem. Soc. (London), 18, 2 (1902). 

3. Rutherford and Soddy; Phil. Mag. (1902), p. 370. 

4. Italics theirs. 

5. Berichte 34, 3776. 

6. See the works of the Curies, Giesel, Elster and Geitel, Marck- 
wald and others. 


understand how in a mineral or salt a radio-active body, perhaps 
resembling one of the constituents, clings to various compon- 
ents throughout many chemical manipulations. It having been 
suggested that uranium might owe its radio-activity to the 
presence of small amounts of polonium or radium, Mme. Curie 1 
states that such could not be true, and adds in another paper, 2 
"the property of emitting rays, * * * * which act on photo- 
graphic plates, is a specific property of uranium and thorium." 
''The physical condition of the metal seems to be of an alto- 
gether secondary importance." "Uranium and thorium alone 
are practically active." 

The power possessed by thorium, as usually prepared, of 
inducing activity, reported by Rutherford and his co-workers, 3 
is most interesting. The brilliant French woman states con- 
cerning uranium: 4 "I have never found any marked difference 
between the relative activities of the same compounds." By 
analogy one may consistently assume the same for thorium. 
The author has obtained similar compounds of thorium frac- 
tions which do differ in their radio-activity, in some cases one- 
being three times as great. 

Metzger 5 has published an interesting and novel method 
for separating thorium from cerium, lanthanum, and didymium, 
depending upon its precipitation from a neutral solution by a 
forty per cent, alcoholic solution of fumaric acid. The writer 
.and Lemly 6 have verified these observations as far as ordinary 
analytical methods are concerned. Applying it to the accepted 
chemically pure thorium, however, we obtained a filtrate con- 
taining less than 0.5 per cent, of the original, which, on evapora- 
tion and ignition, gave a grayish oxide possessing such marked 

1. Revue generate des Sciences, January, 1899; M. and Mme. Curie: 
Compt. Rend., 127, 175. 

2. M. and Mme. Curie and M. Bemont : Compt. Rend. 127, 1215. 

3. Loc. cit. 

4. Ibid. 

5. Journ. Amer. Chem. Soc. 24, 901. 

6. Unpublished work. 


radio-activity by the electrical method that Dr. Pegram stated, 
that it acted as if "salted with radium." This decayed with fair 
rapidity, from 42 to 12.4 in eight days, to 3.3 in nine days more 
(uranium being taken as the standard unit). After thirty-two 
days more it gave 3 and was practically constant. The corre- 
sponding values obtained for the thorium precipitate, which 
constituted virtually the whole, were 0.63, 0.92 and i. Truly 
but one interpretation of these results may logically be had, 
namely, the existence of a radio-active body with thorium, which 
is different from it. Crookes has sounded a timely warning 
against depending upon the photographic method for deter- 
mining the radio-activity, so we have been guided mainly by 
the electrical method. Although by no means comparable to 
the other procedure, yet most interesting observations may be 
had by the photographic method. It has been used to secure 
very rough quantitative results. It aids one much in learning 
of the ft- activity. The a- rays are the most important factor 
in the ionization of gases, upon which depends the electrical 
method. Persistent differences, in radio-activity of the prepara- 
tions had by different chemical methods, have been noted and 
the same method of preparation has given persistent differ- 
ences in radio-activity measured by the same and different 

Radio-active thorium obtained from monazite has been 
resolved by the writer into at least two and most likely three 
different constituents. 1 All these are radio-active, but of differ- 
ent strength. Recently the writer and Zerban have obtained a 
thorium preparation from an inactive South American mineral, 
which is free from any activity whatever. 

Ramsay reported the extraction of a very active body like 
thorium from a new Ceylon mineral. This cubical mineral is 
very radio-active and gives out large amounts of helium, which 
Tyrer has collected in twenty-five liter lots. The constituent, 

i. Thorium; Carolinium, Berzelium. Journ. Amer. Chem. Soc. 26, 
922 (1904). 


resembles thorium and shows an atomic weight of 240 in the 
impure form and may contain the carolinium of Baskerville. 


When pitchblende was dissolved in acid, and sulphuretted 
hydrogen added, the sulphides obtained were very active. On 
purification, a substance similar to bismuth was obtained and 
Madame Curie 1 named this first radio-active element Polonium, 
after her native country. 

Polonium may be partially separated by any one of the 
following three methods: First, the active sulphide, being 
more volatile than bismuth, may be sublimed in a tube between 
250 and 300 C. and the active body is obtained as a black sub- 
stance. Second, the active sulphide is less soluble than the 
inactive one, hence partial separation may be obtained by pre- 
cipitation with sulphuretted hydrogen in a hydrochloric acid 
solution. Third, polonium nitrate hydrolyses more easily than 
bismuth nitrate, therefore the active body is precipitated by 
adding water to the nitric acid solution. 

By using the last mentioned method, which is very slow 
and tedious, Madame Curie 2 obtained a small quantity of ma- 
terial extremely active compared with uranium. Only the bis- 
muth lines were observed in the spectrum, as reported by 
Demargay, Runge and Exner. Crookes 3 observed one new line 
in the ultra-violet and Berndt 4 saw a large number of new lines 
in the same region when he used a polonium of 300 activity. 

Polonium apparently gives radiations that are very easily 
absorbable. Giesel 5 called attention to the fact that the penetra- 
ting power of the polonium radiation is much less than that of 
radium rays, consequently the shadow produced by an object 

1. C. R. 127, 175 (1898). 

2. See her thesis. 

3. Proc. Roy. Soc., May (1900). 

4- Phys. Zeit. 2, 180 (1900). 

5- Ann. Phys. Chem. (1899), n, 69- 


is much sharper and deeper with the former than with the 
latter (Fig. 35). 

Becquerel examined samples of polonium nitrate nearly 
as active as the radium salts then had. The radiations appeared 
to be unaffected by the magnetic field, thus differing from those 
of radium. 

The activity is not constant, but diminishes regularly ac- 
cording to the time. In eleven months Madame Curie found 
that polonium lost one-half of its original activity. This fact 
has caused many to view polonium not as a new element, but 
merely as active bismuth, for it is well known that inactive 
elements in the presence of active ones acquire activity. There 
is another view of the matter, however; namely, the supposed 
presence of a very small quantity of some intensely active mat- 
ter. Polonium is therefore not as yet accepted as an element. 

Fig- 35- 

According to Becquerel, polonium rays do not pass through a thin 
film of black paper, forming a small cylinder enclosed with aluminum or 
mica, upon the bottom of which rests the powder; the radium rays 
readily transverse the envelope. The figure illustrates strikingly the 
difference in the rays. 


Marckwald, 1 entering the discussion as to the -elementary 
character of polonium, reported the rinding of a substance in 
pitchblende similar to polonium, but whose activity did not 
decay with time. A rod of bismuth dipped into the active solu- 
tion obtained from the uranium residues quickly acquired a 
black, intensely active deposit. (See radio-tellurium.) 

Giesel 2 confirmed Marckwald's statement that bismuth im- 
mersed in a solution of Curie's polonium, acquired the property 
of emitting a- rays. Bismuth, platinum, and palladium may be 
rendered highly active by immersion in a solution of radium 
salts. After the metal is carefully washed with hydrochloric acid 
and water, to remove traces of radium, it still emits the a- rays 
strongly. Bismuth becomes mucR more active than the other 
two elements, consequently Giesel insisted that polonium is 
nothing more than bismuth rendered active by contact with 
radium salts. This German scientist also learned that after 
bismuth remained in a one per cent, radium salt solution for 
several days and was then removed and washed with hydro- 
chloric acid and water, it showed intense a- radiation, but no 
^-radiation. The small quantities of bismuth and platinum 
metals that were dissolved in this experiment were precipitated 
with hydrogen sulphide. These sulphides were found to emit 
the /3-rays. This may be ascribed to the adhering radium salts. 
One of the methods for distinguishing the different rays de- 
pends upon the observations of Crookes, Elster and Geitel ; 
namely, the scintillations produced by the a- rays, whereas the 
/?- radiations produce only uniform illumination of the screens. 

The Curies, 3 from various observations, concluded that the 
radio-activity of uranium, thorium, radium, and probably actin- 
ium, is the same and does not vary with time when the radio- 
active substance is brought into the same chemical and physical 
state. If by any particular treatment the substance loses any 
of its activity, it regains it in the course of time. Polonium acts 

1. Berichte 35, 2285 (1902) and elsewhere. 

2. Berichte 36, 23, 68 (1903)- 

3. Compt. Rend. 134, 85 (1902). 



Debierne, 1 who directed the factory work of the Curies, 
obtained from pitchblende an active substance which was pre- 
cipitated in the iron group and which appeared to be very 
closely allied to titanium and thorium, especially the latter. He 
named it Actinium. This substance has never been obtained in 
sufficient purity to give a characteristic spectrum. It should be 
mentioned, however, that the spectrum of thorium itself is 
extremely complicated. Four methods were used by Debierne 
for partial separation, as follows : 

First. The active matter accumulated in the precipitate pro- 
duced by sodium thio-sulphate in hot solutions, made slightly 
acid with hydrochloric acid. 

Second. Titanium was separated by the action of hydro- 
fluoric acid upon the suspended hydrates in water. The actin- 
ium accumulated in the undissolved portion. 

Third. When a neutral nitrate solution was precipitated by 
hydrogen peroxide, the active body accumulated in the precipi- 

Fourth. If the sulphates were treated with a soluble barium 
salt, the barium sulphate which was formed carried down the 
actinium matter. This was separated from the barium after 
conversion into th chloride, by cooking with sodium carbonate, 
filtering, dissolving the precipitate in hydrochloric acid and 
adding ammonia. 

The original material was free from uranium. After sep- 
arating the other known radio-active bodies, radium and polon- 
ium, a preparation 5,000 times as active as uranium was 

Actinium renders gases capable of discharging electrified 
bodies, excites fluorescence in a barium-platino cyanide screen 
and affects photographic plates (Fig. 36). It is said to differ 
from radium in not being spontaneously luminous. 

i. C. R. 129, 593 (1899); 130, 906 (1900). 




D C 

Fig. 36. 

The figure illustrates the action of radium bromide 300,000, "uranies" 
strong, (A and B) and actinium oxide, 10,000 uranies, (C and D) on 
photographic plates through the thin glass of the containers. A and C 
were exposed to the plates, covered with black paper, for two hours. 
Practically no action on the sensitive film was observed for the actinium. 
B and D were allowed to remain fourteen hours. A marked difference 
is observed in the character of the radio-activity of the two substances. 
That of radium is more complex. The term "uranies" was coined by 
Roberts to mean the standard in terms of the activity of metallic uran- 
ium (unity). 

Actinium gives out easily absorbable and penetrating, devi- 
able rays, like cathode streams, and a radio-active emanation, 
which loses its activity in a few seconds. While it resembles 
the thorium emanation, it differs from it in the rate of decay. 


The thorium emanation loses one-half of its activity in one 
minute. 1 

The deviation 2 was found to correspond to positively 
charged bodies moving with a high velocity. The induced 
radio-activity was shown by Debierne in the following manner : 
Two plates were placed at an angle over a tube containing an 
actinium salt. The ions are contained almost exclusively in 
the tube above the salt, but the plates become radio-active. This 
can only be accounted for by a secondary radiation proceeding 
from each ion, as the radiation is deviated in a magnetic or 
electric field as has been established. 

No atomic weight has been obtained for actinium. Hof- 
mann and Zerban 3 obtained the equivalent 63.32 or atomic mass 
value of 253.28 (tetrad.) for a preparation of 2,000 activity. 

Radio- Active Lead. 

Elster and Geitel 4 obtained a very active lead sulphate 
from pitchblende. They were able to extract from this an 
inactive lead sulphate. Therefore, they attributed its activity 
to the presence of more or less radium. 

GieseP obtained a small sample of radio-active lead sul- 
phate from uranium residues which, when wrapped in black 
paper, did not produce any effect upon the photographic plate. 
When surrounded by transparent paper, however, the plate 
was affected. He, therefore, attributed the action to that of 
light rays given off by the phosphorescent substance. He calls 
attention to the fact that lead might contain a very minute 
amount of radium, much less than one is able to detect by 
chemical means, and still be radio-active. 

Hofmann and Strauss 6 obtained a lead sulphate from 
pitchblende, uranium, mica,broggerite, cleveite, and samarskite. 

1. C. R. 136, 446 (1903). 

2. Compt. Rend. 136, 671 (1903). 

3- Berichte 36, 3093 (1903)- 

4- Wied. Anal. 69, 83 (1899). 

5- Berichte 34, 3772 (1901). 

6 - Berichte 33, 3126 (1900). 


which were radio-active. It contained no trace of bismuth, 
barium, (which precluded the presence of polonium and ra- 
dium), titanium, thorium, or uranium. The sulphate was insolu- 
ble in dilute sulphuric acid, but easily soluble in aminoniacal 
tartrate. The chloride showed diminished radio-activity when 
crystallized from hot water, whereas the mother liquor gave 
crystals with increased activity. 

These same workers 1 purified their active lead sulphate 
by converting it into the carbonate and then into the chloride. 
They were able to fraction the sulphate into more active prep- 
arations, which gave a blue phosphorescence when exposed to 
the cathode rays. The spark spectrum gave a characteristic 
line in the violet. 

Potassium iodide converts the sulphate into a mass of yel- 
low crystals, which dissolve in warm dilute sulphuric acid and 
separate again on heating. From a determination of the per- 
centage of the sulphur tetroxide, it was learned that the metal 
present was both bivalent and quadrivalent. The radio-activ- 
ity of the sulphate diminished on keeping, but was entirely 
restored on exposure to the cathode rays. The atomic weight 
of 260 has been assigned to radio-active lead. It resembles 
ordinary lead in most of its characteristics, except that the 
sulphate is strongly phosphorescent. 

They 2 also isolated from broggerite two elements ( ?) of 
the atomic weights 100.92 and 171.96. The former gives a 
yellow sulphate and has little influence on the radio-activity 
of the lead. The strong radio-activity of the other is lost when 
converted into the sulphide. This is obtained again when the 
sulphide is reconverted into the sulphate. 

The chromate 3 of the radio-active lead is not decomposed 
on repeated warming with dilute sulphuric acid, which distin- 
guishes it from ordinary lead chromate. The sulphate acts 

1. Berichte 34, 8 (1901). 

2. Berichte 34, 907 (1901). 
3- Berichte 34, 3O33 (1901). 


upon a photographic plate through aluminum and glass. All 
of the radio-activity is effective in discharging the electroscope. 

Hofmann with Wolfl 1 found that the radio-active lead could 
be concentrated by dissolving the lead sulphide in aqueous 
sodium thio-sulphate. On keeping for several days an active 
black sulphide separated out. Unlike polonium, this radio- 
active lead acted on a photographic plate with great rapidity 
through a sheet of gutta percha. 

Giesel 2 found that the radio-activity of the radio-active 
lead which he obtained diminished with time, whereas Hof- 
mann's preparations preserved their activity. 

Winkler has questioned the method of the determination 
of the atomic weight, but Hofmann has apparently substan- 
tiated his claims. (See Chapter V.) 

Radio -Tellurium. 

Marckwald 3 obtained 1.5 grams of radio-active tellurium 
from six kilograms of bismuth oxychloride which was extracted 
from 2,000 kilograms of pitchblende. This contained only 
about one per cent, of the radio-active constituent. The whole 
was converted into the chloride and precipitated by hydrazine. 
The filtrate was concentrated and heated on a water bath with 
a drop of stannous chloride. In this way four milligrams of 
a dark colored -precipitate were obtained. This radio-active 
substance dissolves in cold nitric acid and may be converted into 
a soluble chloride. Upon the immersion of a copper, tin, or 
antimony plate in the solution, the active substance is deposited 
in a fine state of subdivision, o.oi milligram separated on the 
copper plate. Four square centimetres of this plate illuminated 
a zinc-blende screen so that it was visible to several hundred 

The polonium of. Madame Curie behaves quite differently 
from radio-tellurium, in that its nitric acid solution gives with 

i. Berichte 35, 1453 (1902). 
2 Berichte 34, 3775 (1901). 
3. Berichte 36, 2662 (1903). 


water a yellow to brown precipitate, soluble in acids. The 
polonium of Giesel is also quite different. 

Bismuth dipped into a solution containing radium becomes 
radio-active, but its activity is not comparable with that of 
radio-tellurium. The solution is not at all exhausted. 

Tellurium precipitated by stannous chloride from a solu- 
tion of tellurous acid, containing radium chloride, although 
somewhat active, gives when converted into the chloride, a 
liquid which fails to render active a copper strip immersed in 
it. Therefore, the induced activity is doubtless different from 
the activity of radio-tellurium. 

Marckwald, 1 who entered a discussion on the complicated 
question of the nature of polonium, secured from pitchblende 
a' substance resembling tellurium, which is active, but whose 
activity does not decay with time. The method of separation 
depended upon the insertion of a rod of bismuth into the bis- 
muth chloride solution, obtained from the uranium residues. 
The black deposit which coats the bismuth is very active. Hav- 
ing obtained .6 gram of the substance, he proved that its activ- 
ity did not decay within nine months. 

The chloride was electrolysed for three days ; a bismuth 
cathode and carbon anode were used. The solution became 
inactive. The deposited metal is much more radio-active than 
the original substance. The deposit, which contains a little 
chloride, was sublimed from the bismuth terminal. The metal- 
lic bead obtained was dissolved in nitric acid. The solution gave 
the reactions of bismuth. 

The rays given out did not penetrate paper or other obsta- 
cles, hence they were similar to those given out by polonium. 
They affected a photographic plate, and caused diamonds, zinc 
oxide and other substances to fluoresce brightly. The body 
differed from polonium in the fact that its activity did not decay. 

This method of producing radio-acfive metallic coatings 
has been patented by H. H. Lake, of the firm of Stahmer & 
Co., Hamburg. 2 

1. Ber. Chem. Ges. 35, 2285 (1902), Chem. Zeit. 26, 895. 

2. J. S. Chem. Ind. 22, 1136 (1903). 


According to the periodic table of Mendelejeff, tellurium 
should have an atomic weight less than iodine, whereas it has 
actually been found to be greater. Pellini 1 suggested that this 
might be acounted for by the presence of a small quantity of 
some element, which has a higher atomic weight (about 212), 
similar to tellurium and analogous to the radio-active constitu- 
ents of pitchblende. 


Giesel 2 has obtained from pitchblende a substance which 
he has termed Emanium. It appears to be allied to lanthanum, 
belonging to the cerium group of rare earths. The salts when 
first prepared are not so active, but reach a maximum in about 
a month, remaining so indefinitely; thus being similar to ra- 
dium. 3 The original /3-radiation becomes smaller trie longer 
the substance is kept in solution. Runge and Precht obtained 
a number of new lines in the spectrum, which gave essentially 
the lines of lanthanum and a little cerium. The lines of thor- 
ium, barium, and radium were not present. The anhydrous 
chloride and bromide phosphoresce spontaneously. Glass ves- 
sels in which the substance is kept for a month become violet 
colored ; paper is turned brown and destroyed. 

"If solutions of thorium, lanthanum, cerium, etc., to which 
radium has been added, are precipitated with ammonia and 
washed, the precipitates are adulterated with traces of radium 
and show, besides (3- radiations, remarkably strong a- radiations, 
but yet an emanation similar to the emanating substance." 4 

The discoverer attributes the induced radio-activity of 
many substances rather to the emanating substance than to 
the presence of minute traces of radium. 

A splendid experiment, visible a great distance, may be 
performed by blowing a current of air through tubes contain- 
ing the material against a large screen of Sidots blende. The 

1. Gazetta 33, 11, 55 (1903). 

2. Berichte 35, 3608 (1902) ; 36, 342 (1903). 

3- Ann. d. Phys. u. Chem. 69, 92 (1899). 

4- Giesel, Berichte 36, 342 (1904). 


scintillations are most pronounced and are visible to the naked 
eye, representing a large spinthariscope. 

In studying the radio-activity of thorium, at the request 
of the writer, Dr. H. S. Miner, of the Welsbach Light- 
ing Company, saved certain ammoniacal washings obtained in 
the process for the extraction and purification of thorium oxide 
from monazite sand for the manufacture of gas mantles. The 
ignited residue, obtained from evaporating over 100 liters of 
this liquor, produced a marked effect upon the photographic 
plate and showed nearly three times the radio-activity of thor- 
ium by the electrical method, using the apparatus of Dolezalek. 
The radio-activity remained constant through a number of 
months. The body gave none of the chemical reactions and did 
not show a single line of thorium in the arc spectrum. 

The writer, working with Lichtenthaeler, has obtained 
highly radio-active bodies, tested by the photographic method, 
from thorium, cerium, didyium oxides, and the residual phos- 
phates, extracted by ourselves from North Carolina monazite 
sands. Further, we obtained an extremely active body by pre- 
cipitating the sulphate solution with hydrogen sulphide, which 
perhaps would, but not necessarily, indicate the presence of 
polonium. Apparent verification is thus had of Giesel's work 
on emanium. 

E. Goldstein 1 examined Giesel's emanium as obtained from 
pitchblende and in its chemical behavior it seemed to be related 
to cerium. On account of the small penetrative power of the 
emanation, he assumed that the air exerted a strong absorption 
of the latter so that its effects would be augmented in exhausted 
tubes. This was verified by experiment. His experiments indi- 
cated that the observed luminescence is due rather to a gas, than 
a special form of energy issuing from the substance. When 
cooling by means of liquid air exhausted tubes, where the active 
matter had been introduced, Goldstein observed a very strong 
luminescence on the wall, which, instead of rising in the closed 

i. German Physical Society. 


portion of the tube, seemed to be confined to the zone imme- 
diately above the level of the liquid air. That is, the phenom- 
enon is characteristic of a definite temperature above the tem- 
perature of liquid air. The emanation is given off at the tem- 
perature of liquid air. He does not think that the emanation 
energy in question is identical with that of radium, the distin- 
guishing features being first, the absence of the coloration of 
the tubes, and, second, the excessively low penetration. 

Artificially Active Barium. 

Debierne 1 observed that when a highly radio-active salt 
of actinium is added to a solution of barium chloride, the latter 
becomes radio-active. If the barium be precipitated as sul- 
phate and reconverted into the chloride, the actinium being 
separated by means of ammonia, the barium retains some activ- 
ity. This may be increased, depending upon the time of con- 
tact, till it is several hundred times as active as uranium. It 
is persistent throughout various chemical changes, it ionizes 
gases, excites barium-platino-cyanide, and acts upon a photo- 
graphic plate. Part of the radiation is deflected in a magnetic 
field and the anhydrous chloride is also luminous. This barium 
chloride, rendered radio-active, may be fractioned similarly to 
the radium salts. The salts, however, do not give any of the 
lines of the radium spectrum and their radio-activity gradually 
diminishes in intensity. 


Soddy 2 maintains that radio-tellurium is identical with 
polonium and that there is no justification for the assumption 
of a new element. Soddy acknowledges the existence of five 
radio-active elements ; namely, uranium, thorium, polonium, 
radium, and actinium. They may be distinguished in three 
ways: They all give off a- rays ; all, with the exception of 
polonium, give /3-rays ; uranium, thorium, and radium give 

1. Compt. Rend. 131, 333 (1900). 

2. Nature, March 17, 1904, pp. 461. 


y-rays. Polonium does not, and it is questionable about actin- 
ium. Neither uranium nor polonium gives off a radio-active 
emanation, while thorium, radium and actinium do. Those 
radio-active substances which give off emanations impart activ- 
ity to surrounding objects. That is, substances placed in the 
neighborhood of thorium, radium and .actinium acquire an activ- 
ity which is not permanent. The three substances which give 
off emanations have their respective emanations distinguished 
from one another by the time their activity lasts. The emana- 
tions of radium continue through several weeks, those of thor- 
ium only a few minutes, and actinium only a few seconds. 


C. T. R. Wilson 1 reported the radio-activity of rain and 
snow. Rutherford and Allan 2 studied excited radio-activity 
and its effect on the ionization of the atmosphere. The latter 
regarded the radio-activity of rain and snow as derived from 
the radio-activity of the atmosphere. J. J. Thomson 3 reported 
a radio-active gas in the Cambridge tap water, as did Bum- 
stead and Wheeler 4 for the surface water around New Haven, 
Conn. Adams, 5 considering the former, suggested the presence 
of a small amount of radium in solution. Knetf observed that 
the thermal springs of Karlsbad deposited small yellow tabular 
crystals of barium suphate which were very radio-active. 

McLennan and Burton 7 reported the electric conductivity 
of the atmosphere. The former" has observed the radio-activity 

1. Proc. Camb. Phil. Soc. 12, 17 (1902); 13, 85 (1902). 

2. Phil. Mag. 6, 704 (1902). 

3. Proc. Camb. Phil. S. 123, 172 (1903)- 

4. Am. J. Science (1904). 

5. Phil. Mag. (6), 6, 563- 

6. Sitz. Wien. No. n (1904). Nature 70, 160. 

7. Phil. Mag. 6, 5, 699. 

8. Nature 70, 151 '1904). 


of natural gas, as well as experimented 1 on the induced radio- 
activity excited in the air at the foot of waterfalls. McLennan 
and Burton 2 also learned that metals generally possess more or 
less radio-activity. 

H. Lester Cook 3 reported the penetrating radiation from 
the earth's surface. Borgmann 4 found the Russian muds radio- 
active and that the air could be electrified by metals. Geitel 
found a wire electrically charged and suspended in the air, as 
well as the ends of pine needles, radio-active. 

Elster and Geitel 5 secured a radio-active emanation from 
the air, from the soil, from cellars, mountain tops, mines, etc. 
They 6 also observed the radio-activity of sediments obtained 
from evaporated spring water. 

Miiller 7 verified these observations and suggested the pres- 
ence of another radio-active element accompanying radium. 

Strutt 8 studied the properties of a strong radio-active gas, 
which he obtained from metallic mercury and learned 'that the 
emanation behaved similar to that of radium, reaching one-half 
value in a little over three days. Strutt 9 also determined the 
activity of a number of minerals, mineral waters, and ordinary 
materials. Lester Cooke 10 proved the universal occurrence of a 
penetrating radiation similar to radium. It may have its origin 
in the radio-active matter distributed throughout the earth and 
atmosphere. Himstedt 11 reported the radio-active emanation of 

1. Phil. Mag. 6, 5, 419. 

2. Phil. Mag. 6, 6, 343 (1903). 

3. Phil. Mag. 6, 6, 403 (1903)- 

4. Nature, 70, 80 (1904). 

5. Chem. News 88, 29 (1903). 

6. Phys. Zeit. 5, 321. 
7 Phys. Zeit. 5, 367. 
8. Phil. Mag. 6, 6, 113. 

9- Proc. Roy. Soc. 73, 191 ; Phil. Mag. (6), 5, 680. 
io- Phil. Mag. 6, 410 (1903); Proc. Roy. Soc. 68, 151; 69, 277; 
Nature (1903), 3^9; 391, 4*4, 439- 
ii. Ann. d. Phys. 13, 573. 


water and oil springs, and von Traubenberg 1 considered the 
absorption of the emanations of radium by the tap water of 
Freiburg and other liquids. 

Different meteorological conditions 2 appear to determine 
different degrees of radio-activity of the air. Much activity is 
excited in fog. In cold, frosty weather the activity of the air is 
very high. We have learned that tobacco smoke in the room 
where one is making measurements by means of an electro- 
scope increases the conductivity of the air. These things cause 
variations in the leak of the instruments. 

Concerning the general radio-activity of metals, Voller 3 
has called attention to a flaw in the experiments by McLennan 
and Burton,* who claimed to be able to prove all metals radio- 
active, as the potentials are very small and subject to many 
errors. Hallwachs has pointed out the necessity of taking into 
account all the E. M. F.'s of the electro-metric system. But 
Voller, .on the other hand, says it cannot be denied that the 
spontaneous projection of positive ions by all metals, if con- 
clusively established,, would mean a very important advance in 
our knowledge of the electrical phenomena. 

Himstedt 5 arrived at the conclusion that radio-active bodies 
give off gaseous emanations and are widely diffused through- 
out the earth. These emanations, being absorbed by water or 
petroleum, are afterwards conveyed along by the latter to the 
surface of the earth and are diffused into the air. On account 
of the analogy between these emanations and those of radium, 
he puts forward the belief that the^ are "identical. The ores 
of uranium, from which the radium emanations are derived, 
are therefore either widely diffused or there are other sub- 
stances possessing, perhaps to a lower degree, the property of 
giving off emanations. The absorption co-efficient of water 

1. Phys. Zeit. 5, 130 (1904)- 

2. London Lancet, Aug. 8th (1903). 

3- Phys. Zeit. Oct. I (1903). 

4- Electrician, Sept. n, 1903, p. 839. 

5- Phys. Zeit. Apr. 15 (1904). 


and petroleum, with respect to the emanations, is found to de- 
crease with the increase of temperature. 

Hot fountains have been found which show especially high 
activity. The hypothesis is, therefore, put forward that the 
amount of radio-active material increases for augmenting 
depths. The radio-active components of the earth, conse- 
quently, should have to be allowed for in accounting for the 
temperature of the earth. 

Schuster, 1 referring to the matter of the cosmical radio- 
activity, calls attention to the fact that any physical property 
discovered in one element has always been found to be shared 
by all. The possibility that radio-activity may be a common 
property of all matter is immediately suggested. Radio-active 
bodies, therefore, may be distinguished from other bodies by 
the enormously exaggerated form in which they possess the 

We know that the earth must be charged with negative 
electricity, which must be constantly renewed as there is con- 
stant leakage. Elster and Geitel recently determined that a 
body loses about 1-1/3% f i ts charge per minute. If the air 
near the ground has that conductivity, the earth should lose 
about one-half of its charge in an hour. There can be little 
doubt, therefore, but that we are living in an electric field 
through which negatively charged particles are constantly 
driven and which possesses an electric conductivity similar to 
that found in the neighborhood of radio-active bodies. The 
radio-activity of the ground air or water may thus be the con- 
sequence of the emanations of a radio-active earth. 

Schuster also pointed out the possibility of a correspond- 
ing radio-activity of the matter in celestial bodies. 

Rutherford, in a lecture before the Royal Institution in 
London, stated that the amount of radium present and uni- 
formly distributed throughout the earth would be sufficient to 
account for all the heat lost from that body. On the assump- 
tion that this is true the period of time for the cooling of the 
earth till it becomes uninhabitable, as calculated by Lord Kel- 
vin, may be extended a few million years. 

i. Chem. New? 88, 166 (1903). 

6 9 



Variations in the radiations of thorium have been observed, 
by the electrical method, when the substances were examined 
in open vessels. Owens 1 found that this was caused by the air 
currents. When active matter was introduced into a closed 
glass vessel the activity increased with time, finally reaching a 
constant, which could be reduced by passing a stream of air 
through the vessel. It was noted, also, that the radiations 
passed through several thicknesses of paper, which absorbed 
the a- rays. Rutherford 2 discovered the emission of radio- 
active particles from thorium compounds and named them 

The ionizing substance acts upon a photographic plate and 
diffuses through porous substances similar to a gas. (Fig. 36.) 
It may be swept along by a current of air, passed through cot- 
ton-wool, and bubbled through a solution of caustic potash 
without any loss of activity. Thus it differs from the ions pro- 
duced in gases by the action of radio-active substances. The 
emanation cannot be dust of radio-active substances, which 
would be screened out by the cotton-wool filters. Hydrogen 
peroxide possesses the power of diffusing rapidly through por- 
ous substances and acting upon a photographic plate, but it is 
not radio-active. It is the radiation from the emanation, and 
not the emanation itself, that produces the two characteristic 
ionizing and photographic effects. (Fig. 37.) 

i. Phil. Mag., Oct. (1899). 
2.. Phil. Mag., Jan. (1900). 


To Rutherford and his co-workers are we indebted for 
most of our knowledge of these and other emanations. Dorn 1 
made similar discoveries later with radium compounds. The 
radium emanation loses its radio-activity at a different rate, 
although it possesses many similar properties. Both behave 
like a temporarily radio-active gas mixed in minute quantities 
in the air in which they are conveyed. 



Fig. 36. 

The apparatus may be used to demonstrate that the emanation of 
radium is a gas and follows Gay-Lussac's law. The bulbs, A and B, 
connected by a glass tube are evacuated, filled with the emanation and 
placed as shown in the diagram. A rests within a cylindrical con- 
denser, such as shown in Fig. 36, while reservoir B rests within a 
constant temperature bath which may be heated by electricity. The 
radiation of A possesses a definite value for one temperature, increasing 
with the elevation of the temperature of B. The quantity of the 
emanation which has been driven out corresponds to that which it 
should be according to Gay-Lussac's law. 

The emanations are given off more generously by the 
radium compounds by heating, or on solution in water. Curie 

i. Abh. d. Naturforsch. Ges. fur Halle (1900). 


Fig- 37- 

The figure shows apparatus, which may be used to illustrate the 
diffusion and condensation of the emanation, in short demonstrate its 
gaseous nature. Bulb A contains a radio-active solid or its solution. 
B is coated on the inside with Sidot's blende, as is also the small bulb C. 
Inserted in the connecting tubes, t and t' are the glass cocks R and 
R'. R" serves to disconnect the apparatus from a vacuum pump. The 
emanation collects in A, R being closed, if the radio-active solution be 
allowed to stand ; if a solid be used, the experiment may be hastened by 
gently heating the bulb. B and C are evacuated, R" closed. On opening 
R, the emanation which has caused a slight glow in A, flows into B, 
which becomes quite luminous. On closing R, placing C in a Dewar 
bulb containing liquid air and opening R', the emanations are drawn 
into C; after a time close R' and remove the apparatus. B will have 
ceased glowing and C is exceedingly luminous in a dark room. 

and Debierne 1 found that if radium preparations were placed 
in a vacuum tube, the vacuum was continually weakened. 
Giesel 2 observed that gases were evolved from solutions of 
radium bromide, which Runge and Bodlander found, by spec- 
trum examination, to be mainly hydrogen with about one- 
tenth oxygen. m Ramsay and Soddy 8 found that 50 m.g. of 
radium bromide would evolve 0.5 c.c. of gas per day. 

P. Curie 4 and Rutherford and Soddy 5 determined the rate 
of decay of the activity of the emanation, which was found to 

1. C. R. 132, 768 (1901). 

2. Berichte d. Chem. Ges. 35, 3605 (1902). 

3. Pro. R. Soc. 72, 204 (1903). 

4. C. R. 135, 857 (1902). 

5. Phil. Mag., April (1903)- 


be in accordance with an exponential law with the time, falling 
to one-half value in about four days. Curie* further determined 
that the rate of decay was not materially affected through such 
a wide range of temperatures as +450 to 180 C. Ruther- 
ford and Soddy 2 showed that the rate of decay for thorium 
emanations was practically the same at ordinary temperature 
a^ 1 at that of liquid air. 

Debierne 3 discovered the emanations of actinium: The loss 
of activity is most rapid, falling to one-half value in a few 
seconds. Giesel has obtained an intensely active emanation 
from the ''emanating substance," which latter resembles lan- 
thanum and cerium. By placing moist radium bromide on 
the screen, Giesel 4 noted the effect the radium emanation has 
upon a screen of phosphorescent zinc blende. With the slight- 
est motion of the air the luminosity of the screen is observed to 
move in accordance with the air current. The same result 
could be observed by placing a small bit of the bromide in a 
tube and blowing air through the tube against different por- 
tions of the screen. Screens of barium-platinum cyanide and 
calcium sulphide did not become luminous under similar con- 
ditions. When the screen was charged with negative electricity 
the luminosity was most marked 

The phenomenon upon which the spinthariscope of Sir 
William Crookes 5 depends is based upon the bombardment of 
the zinc sulphide screen by the emanations. (Fig. 38.) Refer- 
ring to this, Elster and Geitel 6 noted their previous observation 
of numbers of stars on an insulated zinc sulphide screen. A 
calcium tungstate screen showed only general or ordinary phos- 
phorescence and no scintillations. Geitel 7 found the star-effect 

1. C. R. 136, 223 (1903). 

2. Phil. Mag., May (1903). 

3. C. R. 136, 146 (1903). 

4 Berichte Chem. Ges. 35, 3608 (1902). 
5- Chem. News 87, 241 (1903). 
6. Phys. Zeit. May (1903). 

7 Aus der Denkschrift der Komission fiir luftelectrische'Forschun- 
gen, Miinchen (1903), Chem. News 88, 29. 


produced by soil emanations on a Sidot's screen charged nega- 
tively to 2000-3000 volts. 

Crookes and Dewar learned that the scintillations ceased 
when the radium was cooled by liquid air, but the brilliancy 
was quite as marked when the Sidot's screen was cooled and 
the radium compounds were at normal temperatures. The high- 
est vacuum attainable by cold does not affect the scintillations. 

Fig. 38. 

The Crookes Spinthariscope and the principle involved. On the 
end of wire pointer, a, is placed a tiny speck of a strong radium com- 
pound. This may be caused to move from place to place in front of a 
zinc-blende screen, E, from which it is less than a millimeter distant. 
Upon examining the screen in the dark, by means of the strong lens, L, 
which may be focused, one sees numerous beautiful scintillations, 
resembling the play of moonlight uporr a rippling lake. The impression 
is given of the bombardment of the screen by many tiny particles, each 
flashing as it strikes the restraining phosphorescent substance. 

Curie and Debierne 1 learned that in a vacuum a gas was 
given off from radium which produced excited activity on the 
glass walls of the vessel. The walls fluoresced, rapidly dark- 
ened, and affected the photographic plate. This gas did not 
show any lines in the spectrum, other than those of carbon 
dioxide, hydrogen and mercury. They, also, learned 2 that 
many substances were phosphorescent under the action of the 

1. C. R. 132, 548 (1901). 

2. C. R. 133, 931 (1901). 


emanation. They found in general that 'substances which are 
phosphorescent in ordinary light become luminous, especially 
zinc sulphide. They also observed that phosphorescence was 
produced in Thuringian glass, showing most marked effects. 
Kunz and the author 1 noted that willemite is an even more 
sensitive detector of the ft- and y-rays than barium-platinum 
cyanide. Rutherford condensed the emanations of radium upon 
a crystal of that mineral with most brilliant fluorescent effects. 
The writer and Lockhart caused certain diamonds (tiffanyite) 
and minerals, as greenockite and wollastonite, to glow bril- 
liantly when the emanations were condensed upon them. Pecto- 
lite and the spodumenes, especially the variety kunzite which 
responds to the (3- and y-rays, did not phosphoresce 2 . Soddy 
reports an observation contrary to this. The amount of excited 
activity deposited is proportional to the amount of emanation 
present, the distribution varying as the distance. Crookes 3 has 
caused white diamonds to assume the rare greenish color as a 
result of the action of the emanations. The jewels were buried 
for several weeks in radium bromide. 

Rutherford and Soddy 4 measured the emanating power of 
different thorium compounds and learned that they varied very 
much, although the percentage of the thorium present in the 
compound was not very different. Rutherford 5 learned that 
the emanating power of ordinary thorium oxide is increased 
several times by heating the substance to a dull-red, but when 
heated to a white-heat the emanating power was greatly 
reduced. When the heat is maintained red, the emanation 
apparently continues to escape and the substance returns to its 
original value on cooling ; whereas, after heating to a white- 
heat, on cooling it has only about ten per cent, of the original 

1. Science (N. S.), 18, 769 (1903). 

2. Science (N. S.), 18, 303 (1903). 

3. Chem. News 90, i (1904). 

4- Trans. Chem. Soc. 321 (1902). 

5- Phys. Zeit. 2, 429 (1901). 


value. It has become "de-emanated." With lower tempera- 
tures, the emanating power of thorium decreases quite rapidly 1 
being about ten per cent, of the original at the temperathre of 
solid carbon dioxide. When the temperature is allowed to rise 
back to the ordinary, the original value is recovered. Ruther- 
ford and Soddy also verified the observations made by Dorn 
that the emanating powers of thorium and radium compounds 
are much affected by moisture, being greater in a moist than 
in a dry gas. 

Thorium and radium compounds which have been de-ema- 
nated appear to recover the emanating property with time. It 
is not known whether this is due to a renewal or alteration of 
the substance which produced the emanation, or whether the 
intense heating simply changed the rate of escape of the ema- 
nation from the solid. The physical properties of thorium 
oxide are altered by intense ignition. According to Rutherford 
the color changes from white to pink and the oxide becomes 
denser 2 and is less soluble in acids. He dissolved a de-emanated 
oxide, precipitate'd it as hydroxide, and again converted it into 
the oxide. At the same time a sample of the ordinary thorium 
oxide was subjected to similar treatment. "The emanating 
power of both of these compounds was the same and was from 
two to three times greater than that of ordinary thorium." It 
should be noted that Rassignal and Gimingham 3 have deter- 
mined the rate of decay of the emanations as 51 and not 60 
seconds, as given by Rutherford. 

As a general rule, an increase of temperature in a solution 
of a salt of thorium or radium greatly increases the emanating 
power. From this it would seem that the original power of 
producing emanation persists in the atom. (See Chapter V.) 

1. Rutherford and Soddy, Phil. Mag., Nov. (1902). 

2. See the author's paper, "Thorium; Carolinium, Berzelium;" 
Journ. Am. Chem. Soc. 26, 922 (1904). 

3. Phil. Mag. (6), 8, 107. 


Henning 1 found that the radio-activity induced in metallic 
wires by thorium oxide depended upon the surface area of the 
wire, the volume of the containing tube, the fall of potential, 
and the thickness of the layer of the thorium oxide. 

Rutherford and Soddy, 2 in a comparative study of the 
emanations of radium and thorium, found that as far as that 
property is concerned, they are closely allied, both producing 
radio-active emanations, and they in turn excite radio-activity 
in surrounding objects. The difference is very marked, how- 
ever, in the rate at which the activity of the emanation decays. 
The intensity of the thorium emanation falls to one-half value 
in one minute, and that of the radium in about four days ; while 
the excited radio-activity due to radium decays much more 
rapidly than that produced by thorium. 

Curie and Danne* have shown that the radium emanation 
is absorbed by lead, paraffin and caoutchouc. 

Touching the rate at which emanations are given off by 
solid radium compounds or when they are in solution, Ruther- 
ford and Soddy 4 have called attention to the following interest- 
ing point: 

By theory, the amount of emanation stored up in a non- 
emanating radium compound is likely to be nearly 500,000 
times the amount produced per second by the compound. -"By 
experiment the figure obtained was 463,000. Taking other 
things into consideration, this would indicate that the produc- 
tion of, or ability to produce, the emanation is the same with 
the solid compound as when in solution. It is occluded in the 
solid, and therefore given off slowly, while in a solution it is 
given off as fast as produced. Rutherford is of the opinion 
that the occlusion is not connected with the radio-activity of 
radium. The apparent" occlusion of helium by minerals is 
analogous. The gas is driven out only in part by heat, com- 

1. Ann. Phys. (IV), 7, 562 (1902). 

2. Phil. Mag. (IV), 5, 445 (1903). 

3. Compt. Rend. 136, 364 (1903). 

4. Phil. Mag., April (1903). 


pletely by solution. The writer and Lockart heated nearly all 
the rare-earth minerals and condensed the gases evolved by 
liquid air. All the helium bearing minerals gave off an emana- 
tion or something of a similar nature, which on refrigeration 
caused diamonds and a Sidot's blende screen to fluoresce. Other 
radio-active minerals, not containing helium, failed to respond 
in a like manner. Strutt 1 heated several minerals, samarskite, 
pitchblende, fergusonite, malacone, zircon, and monazite, col- 
lected the emanation evolved and measured the rate of decay. 
No new emanation was recognized. By drawing air over the 
cold minerals he learne.d that only a very small portion of the 
emanation is given out unless they be heated. All the minerals 
used contained helium and one, malacone, has been shown by 
Ramsay and Travers 2 to contain argon as well. 

The question of the origin ^f the emanations of thorium, 
which according to Rutherford and Soddy 8 are produced by 
thorium-X and not thorium itself, present much that is of inter- 
est. Thorium oxide, freshly prepared by heating the hydroxide 
produced by precipitation with ammonia, shows no emanating 
power. In a month it has nearly reached a maximum in its 
recovery. The thorium-X, obtained by evaporating the filtrate 
from the ammonium hydroxide precipitation, gives out profuse 
emanations. The emanating power decreases rapidly and by 
the time the thorium has recovered its normal activity, the 
emanating power of the thorium-X has nearly disappeared. 
Considering the rates of decay and recovery, apparently the 
radiations are produced as thorium-X is changed into the 
emanation. With radium, however, no intermediate stage 
radium-X has "been observed. Rutherford regarded the 
emanation as being produced directly from the element. 

The emanations of radium and thorium were thought at 
one time to give rise only to a-rays. Curie and Debierne 4 found 

1. Proc. Roy. Soc. 73, 191. 

2. Proc. Roy. Soc. 64, 131. 

3. Phil. Mag., Nov. (1902). 
4- C. R. 133, 931 (1901). 


the amount of excited activity in a closed vessel containing a 
radium compound unaffected by the pressure and nature of the 
gas. The rate of decay of the emanation has been shown to be 
the same under all conditions of concentration, pressure and 
temperature, provided the rate of supply of the emanation be 
constant. (Fig. 39.) 

Fig. 39- 

Rendering bodies active in a closed receptacle through the influence 
of the emanations. The radium salt is placed in a small dish, a, near 
various substances, A, B, C, D and E, it matters not what be their com- 
position (lead, copper, glass, cardboard, ebonite, etc.)- These sub- 
stances acquire activity, may be removed, and their activity measwred. 
The activity increases from the beginning according to the time which 
the substance remains in the receptacle. A limit-value is reached after 
a certain length of exposure. 

Chemical Nature of the Emanations. 

In their earliest experiments Rutherford and Soddy 1 sub- 
mitted thorium emanations, obtained by passing air over thor- 
ium oxide, to a most stringent treatment. They found it unal- 
tered after being heated by electricity to the highest tempera- 
ture attainable, when passed over platinum black, cold and hot, 
red hot lead chromate, magnesium powder, and zinc dust. The 

i. Phil. Mag., Nov. (1902). 


only gases known to withstand such drastic treatment are those 
of the argon family. 

Later Rutherford and Soddy 1 sparked the emanation from 
radium in a glass tube, containing oxygen and an alkali, heated 
it red hot in a magnesia lime tube for several hours, and ob- 
served no diminution in its rate of discharge. They learned 
that a tube containing a large amount of radium emanations 
phosphoresced brightly under the influence of the rays given 
out. The removal of the emanations from one point to another 
in the tube was easily observed in a darkened room by the 
luminosity of the glass. The luminosity of the emanation in- 
creased when the gas was compressed. 

Rutherford and Brooks 2 and Curie and Danne, 3 as reverted 
to, learned that the emanation of radium, like a gas, always 
divided itself between two connected reservoirs in proportion 
to their volumes. By determining the co-efficient of the diffu- 
sion of the emanation in the air, they learned that the molecular 
weight of the gas must be large. The same was demonstrated 
for thorium. Crookes 4 directed attention to the difference in 
the rate of diffusion of the "radiant matter" of radium, actin- 
ium, and polonium through air. The last is the slowest. The 
"emanations" from hydrogen peroxide are not carried through a 
tube by air. 

Wallstade, 5 by determining the co-efficient of the diffusion 
of radium emanations into various liquids, arrived at the same 
conclusion as to the gaseous nature of the emanations. 

Rutherford and Soddy 6 learned that the emanations from 
thorium and radium were condensed at a temperature of liquid 
air. By placing a phosphorescent zinc sulphide screen, or a 
small piece of willemite in a tube, the presence of the emana- 
tions is readily observed through the glowing of either of these 

1. Proc. Roy. Soc. 72, 204 (1903). 

2. Chem. News (1902). 

3- C. R. 136, 1314 (1903)- 

4 Proc. Roy. Soc. 69, 413 (1902). 

5- Phys. Zeit. 4, 721 (1903). 

6. Phil. Mag., Nov. (1002), and (6), 561. 



substances. The luminosity of the screen is due in part to the 
radiation from the emanation and in part to the excited radia- 
tion caused by it. The accompanying figure (Fig. 40) illus- 
trates the very simple methods for the condensation of the 
emanations. The temperature of the condensation of the thor- 
ium emanation is not sharply defined, but is probably 120 
C, while the temperature for the radium emanation is about 
150 C. Their actual quantity is almost infinitesimally small. 
They are invisible and unrecognizable, but their presence is 
readily detected by their property of radio-activity. 

Fig. 40. 

Simple apparatus for condensing the emanations. A radium compound 
or other radio-active substance giving emanations is placed in small tube, 
A, connected by heavy rubber tubing to another tube, which projects 
through a two-hole rubber stopper nearly to the bottom of the thick- 
walled test-tube (C). The exit tube, also provided with a cock, passes 
from just within the test-tube through the stopper to the vacuum pump. 
Within the test-tube may be placed a small piece of Willemite (Kunr 
and Baskerville), a diamond, or zinc sulphide screen. The tube is 
exhausted by opening cock E, B remaining closed. After exhaustion E 
is closed, C placed in liquid air in the Dewar bulb (D). A is gently 
heated, B opened and at once the emanation rushes over and is con- 
densed on the materials mentioned. The glow is very beautiful. By 
closing B the imprisoned emanation may be held for hours or days. 












Liquid Air. 

\ ' 

Fig. 40 A 

The emanations from thorium and from radium are quite 
distinct from each other in two particulars : first, the differ- 
ence in condensation, as just noted ; and second, their difference 
in radio-activity. The rate of decay of the radium emanation 
is about 5000 times slower than that of the thorium emanation. 

As a result of the investigation of the heat emission of the 
radium emanation, it has been learned by Rutherford and 
Barnes 1 that the emission corresponds, approximately, to the 
activity as measured by the a-ra)^s. That is, it accompanies the 
expulsion of the a- particles and is proportional to the number 
expelled. The emanation is responsible for about seventy per 
cent, of the heat effect of radium. The amount of the emana- 
tion is extremely small, but it has been calculated by Rutherford 
that one c.c. of the emanation at standard pressure and tem- 
perature would emit about 3x1 o 7 gram calories of heat. This 
would indicate that heat would be produced at such a rate as 
to melt an ordinary glass tube which might be used to contain 
the emanation in quantity. 

"If the atomic weight of the emanation is taken to be about 
200, it can be calculated that one pound weight of the emanation 
would initially radiate heat at the rate of about 8000 horse- 
power, and in the whole course of its heat emission would radi- 
ate an amount of energy corresponding to 40,000 horse-power 

i. Phil. Mag. (6), 207 (1904). 





A vacuum is formed in this reservoir through the tube, T, and air 
charged with emanation is afterward let in from a reservoir, A. The 
tube, A, contains a solution of a radium salt, and the emanation dis- 
engaged has accumulated in the gaseous part. As soon as the cock, R, 
is opened, the reservoir, B, becomes very luminous, and the light 
emitted by the sulphide of zinc is sufficiently bright to permit of reading 
being done at a distance of 4 or 8 inches from the tube. 

days. In order to obtain such an amount of emanation about 
seventy tons of radium would be required." 1 

i. "Radio-activity," Rutherford, p. 247, MacM. Co. 


Beilby 1 found that glass was decomposed in the neighbor- 
hood of certain hot metals, as gold and platinum. This inten- 
sification of chemical action he attributed to the emanations 
from the metals, although they are not radio-active, as the term 
is used. 

Sir William and Lady Huggins 2 photographed the phos- 
phorescent spectrum of a radium compound by a 72-hour ex- 
posure. They are reported 3 as having found five of the eight 
lines observed as coincident with helium. This appears to have 
been erroneous, as the lines were really found to have agreed 
in position and intensity with the band spectrum of nitrogen. 
Later Crookes and Dewar 4 learned that the nitrogen spectrum 
did not appear when the radium bromide was placed in a highly 
exhausted quartz tube. Yet Curie and Dewar 5 secured notable 
amounts of nitrogen which was occluded by the purest radium 
bromide. .4 of a gram of pure dry radium bromide were left 
three months in a glass bulb connected with a small Geissler 
tube in a mercury manometer, a high vacuum being made in 
the whole apparatus at the beginning. During the entire three 
months one cubic centimeter of gas per month at atmospheric 
pressure was given off continuously from the radium salt. 
Spectroscopic examination showed only the presence of hydro- 
gen and mercury vapor, the former doubtless due to a small 
amount of water, native with the radium salt and decomposed 
by the radium. The same sample was taken to England and 
used by Dewar at the Royal Institution for measuring the heat 
given off at low temperatures. It was in a quartz bulb provided 
with a tube of the same substance. The bulb was evacuated 
and the tube heated to the fusion point of salt. The gas given 
off by the bromide was collected by a mercury pump. After 
passing through a set of new tubes, cooled by liquid air, which 

1. British Association, Southport Meet. (1903), Chem. News 88, 178. 

2. Proc. Roy. Soc. 72, 196 and 409 (1903). 
3- Science (N. S.), 18, 186 (1903). 

4- Brit. Assoc. (1903). 

5- Compt. Rend. 138, 190. 


condensed the greater part, the remainder of the gas was col- 
lected in a test tube over mercury. This amounted to 2.6 c.c. 
at atmospheric pressure. Part of the radium emanations was 
brought over and was radio-active and luminous. The light 
given off by the gases in the test tube, after three days' expos- 
ure with a photographic quartz spectroscope, gave a discon- 
tinuous spectrum with three lines coinciding with the three 
principal bands of nitrogen, namely, 3,800, 3,580, and 3,370. 
The glass tube took on a deep violet hue and half the volume 
of gas was absorbed during the three days. On passing a 
spark through the gas in a Geissler tube, the nitrogen bands 
also appeared. On condensing nitrogen with liquid hydrogen, 
a high vacuum was produced in the Geissler tube and the spark 
showed only the nitrogen present. The quartz tube was heated 
until the bromide of radium melted and deprived of all the 
occluded gases, sealed by an oxy-hydrogen blow-pipe, when 
the vacuum was made, and carried to Paris. Twenty days 
after the sealing Deslandres examined it spectroscopically by 
illuminating the tube with an induction coil, using two rings 
of tin foil around the tube as the poles and secured the entire 
spectrum of helium. This was noted even after an exposure 
of three hours with the quartz spectroscope. 

These observations were in accord with the analogous 
investigations of Ramsay and Soddy 1 . 

Rutherford and Soddy 2 first suggested that the emanation 
might consist of helium. The latter carried the problem to the 
master Ramsay, whose laboratory possessed superb facilities 
for handling and investigating small amounts of gases. They 
removed the hydrogen and oxygen, liberated in large quantities 
from a water solution of the bromide, condensed the emanation 
and carbon dioxide by liquid air and found the characteristic 
D3 line of helium. Later they found not only the complete 
spectrum of helium XX- 6677, 5876, 5016, 4972, 4713 and 
4472, but three other lines which were not identified, namely, 
XX- 6180, 5695, and 5455. 

1. Compt. Rend. 138, 190. 

2. Nature 246 (1903), and Proc. Roy. Soc. 72, 204. 


For a fuller discussion of the emanations see Chapter V. 

Excited Radio- Activity. 

Substances in contact with radio-active bodies acquire the 
power of affecting a photographic plate, and ionizing gases. In 
making certain radio-active experiments, therefore, it is of the 
utmost importance that precautions be taken to avoid the pres- 
ence of other radio-active substances in the room. 

The Curies 1 first observed this property of inducing activity 
by radium and Rutherford 2 noted it for thorium. Solid sub- 
stances placed within a closed vessel, which contains an ema- 
nating compound, become radio-active. The intensity of the 
radio-activity varies directly with the proximity. With radium 
preparations it is different. After an exposure of several hours 
the excited activity is independent of the position or composition 
of the plates. Mica, ebonite, cardboard, and copper exhibit 
equal amounts of activity. It is dependent upon the extent of 
surface exposed. (See Fig. 39.) 

Becquerel 3 examined the secondary radio-activity of metals, 
which was attributed to the absorption of the incident radia- 
tion. The phenomenon appeared to correspond to that of fluor- 
escence or phosphorescence with regard to light and analogous 
to the secondary rays derived from Rontgen rays discovered 
by Saginac. They are less penetrating than the original, but 
consist of portions, (a) not deviable by a magnetic field, but 
easily absorbed, (b) deviable and apparently identical with 
cathode rays, and (c) not deviable, but very penetrating. 4 

This property of exciting radio-activity appears to be due 
to the emanatio'ns and proportional solely to the amount pres- 
ent. It may be concentrated upon the negative electrode in a 
powerful electric field. 

1. C. R. 129, 714 (1899). 

2. Phil. Mag., Jan. and Feb. (1900). 

3- Compt. Rend. 132, 7. 

4- Compt. Rend. 132, 7, 12, 371 (1901). 


Fig. 42. 

Residual activity. The pen was radiographed by a glass tube, which 
contained 5 mgms. of radium bromide, but which had been empty a 

The activity which platinum wire acquires by being placed 
in thorium solutions may be removed by acids like nitric, hydro- 
chloric and sulphuric. 1 The deposited radio-active matter 
may be largely removed by scrubbing the wire with emery 
paper. No increase in the weight of the wire has been observed 
before or after it becomes active. No difference is noted under 
the microscope. Whatever it is, therefore, it must be vastly 
more active than radium itself. Rutherford has termed this 
"radio-active matter" Emanation-X, as it is quite distinct 
chemically and physically from the emanation which produces 
it. This we appreciate at once when we recall that the emana- 
tion is a gas, unaffected by chemicals, while the emanation-X 
is a solid and readily soluble in acids. Platinum wire becomes 
active by exposure to the emanations of thorium, but loses its 
activity when raised to a white-heat. Gates 2 learned that the 
activity was not destroyed, however, but transferred to the walls 

1. Rutherford, Phil. Mag., Feb. (1900). 

2. Phys. Review, p. 300 (1903). 


of the vessel in which the heating had taken place. The same 
was learned of activity induced by radium. 

Miss Brooks has shown that dust particles, as other solids, 
acquire radio-activity when enclosed in the presence of emana- 
tions. M. and Mme. Curie 1 found that substances after a long 
exposure to radium did not lose all of their acquired activity. 
Giesel 2 has found that the radiations from an excited platinum 
wire consist entirely of a-rays. Rutherford 3 found the residue 
from a solution of the deposited matter after evaporation re- 
tained its activity. It was retained when it was enveloped in a 
copper coating electrolytically deposited. Von Lerch 4 studied the 
emanation-X of thorium and learned that copper or magnesium 
wires served to take up most of the active matter. When these 
metals were dissolved and precipitated as different compounds 
the activity remained and decayed at the normal rate ; namely, 
one-half within 1 1 hours. 

Fig. 43- 

Induced radio-activity. The key was radiographed with water 
rendered active by allowing a tube of radium salt to remain in it some 
time and then removing it. 

Barium sulphate also carried down the emanation-X by 
precipitation. Different metals dipped into active solutions 
varied in their conduct. Zinc removed almost all of the activity. 
Iron, nickel, aluminum, copper, lead and cadmium, also, became 
active, while platinum, palladium and silver did not. Pegram* 

1. Thesis, 1903, 116. 

2. Ber. d. deutsch. Chem. Ges. 36, 2368 (1903) 

3. Rutherford, Phys. Zeit. 3, 254 (1902). 

4. Annal. (4), 745 (1903)- 

5. Phys. Review, Dec. (1903)- 


electrolyzed thorium solutions obtaining a radio-active deposit 
of lead peroxide on the anode from the commercial and the 

Fig. 43- 

This is a radiograph of a gold fish which had been placed in water 
rendered radio-active by having suspended in it for twenty-four hours 
a closed tube containing ten milligrams of radium of high activity. By 
this process the water was rendered radio-active and the fish was then 
placed in the water, and although the radium had been entirely removed, 
the fish itself was rendered radio-active, and when placed on a photo- 
graphic plate, photographed itself by its own radio-activity. 

Fig. 44. 

Induced radio-activity. The fish made the auto-photograph after 
being subjected to the action of radium bromide, 300,000 activity. 



so-called chemically pure salts. With pure preparations fur- 
nished by the author no visible deposit was found, but the 
anode was active. Its activity decayed to half value in an hour, 
whereas the rate was 1 1 hours for the commercial preparation, 
the normal rate determined for all the thorium preparations 
hitherto used. This emphasizes a point to which the author 
has frequently directed attention ; namely, that most investiga- 
tions on the activity of thorium have not been made with 
preparations of sufficient purity. Nor have preparations been 
used whose life-history has been known. 

Rutherford and Barnes 1 determined the heating effect of 
radium emanations. This can best be illustrated, as shown by 
Rutherford : 

Active products 


Percentage pro- 
portion of total 
activity meas- 
ured by rays 

proportion of 
total heating 

Radium freed from 
active products 

a rays 



Emanation X(ist change) 

a rays 
a rays 

18 1 



(2d change) 
(3d change) 

No o- rays 
a, (3 & y rays 



42 J 


The heating effect which accompanies the expulsion of the 
a- particles appears to be approximately proportional to the 
number expelled. 

Rutherford 2 learned that under low pressures the excited 
activity produced by thorium is found on both anode and 
cathode, it matters not what the strength of the electric field 
may be. 

1. Phil. Mag. (VI), 7, 202 (1904). 

2. Phil. Mag., Feb. (1900). 


Curie and Debierne 1 learned that the amount of excited 
radio-activity produced by a radium compound was much re- 
duced when the gas within the vessel was kept at a low pres- 
sure. They 2 also learned that induced activity would result 
from the presence of a solution of a radium salt. The action 
is more regular and intense when a solution is used. It pro- 
duces phosphorescence of glass. This is independent of the 
position of the radium solution provided sufficient time be 

The excited radio-activity is attracted to the cathode in a 
strong electric field. Fehrle 3 learned that excited activity fol- 
lowed the lines of force in an electric field. It appears that the 
radio-active matter, therefore, is transported by positively 
charged carriers. 

Giesel 4 reports that his "emanating substance" gives rise 
to a type of radiations which he termed E-rays. By electrifying 
a zinc sulphide screen negatively, more brilliant luminous effects 
were produced, which would indicate that the carriers of the 
excited activity of his emanation substance have a positive 
charge. Batelli and Maccarone, 5 by using an especially sensi- 
tive electrometer of small capacity, suitable for working at 
ordinary or liquid air temperatures, found that the emanation 
carries no charge. They are not atomic residues which the 
positive ions have lost, but the positive ions themselves. McClel- 
land, 6 also, arrived at the same conclusion. 

Debierne 7 showed that barium could be rendered artificially 
active by precipitation from a solution of actinium. A very 
active barium chloride was made in this way, concentrated like 
radiferous chloride, but no spectroscopic lines of radium were 

1. C. R. 132, 768 (1901). 

2. C. R. 133, 23, 931. 

3. Phys. Zeit. 3, 130 (1903). 

4. Berichte 36, 342 (1903). 

5. Atti. R. Acad. d. Lincei Roma (5), 13, 539 (1904). 

6. Phil. Mag. 6, 355 (1904)- 
7- C. R. 131, 137 


obtained. The activity of the barium decayed to about one- 
third its value within three months. 

Debierne, 1 also, obtained a large amount of emanation 
from actinium. Its activity decays very rapidly. The emana- 
tion produced excited activity on adjacent bodies. He attrib- 
uted the excited activity of actinium to "ions activants." 

The induction of radio-activity and ionization of gas are 
quite distinct from one another. Therefore, the actinium 
emanation must be regarded as containing two sorts of energy. 2 
That is, the substance containing actinium seems to emit a sec- 
ond emanation which decays much more slowly than the first 
one described. 

Giesel, four years ago, found that a stick of bismuth would 
become active when placed in a radium solution. He intimated 
that polonium was practically radiferous bismuth. Madame 
Curie repeated the work by fractionation and obtained a bis- 
muth two thousand times as active as uranium. 

Again, Giesel 3 found that his bismuth plate remained active 
after every effort had been made to remove all traces of radium. 
It gave out only a-rays and therein resembled polonium and 

Mme. Curie 4 developed a law for the dissipation of excited 
radio-activity in an unconfined air space. The intensity for 
radium is reduced to one-half value in twenty-eight minutes. 
For actinium and thorium the loss requires greater time. Within 
a closed space, the emanation from radium may be said to dis- 
appear spontaneously as a function of the time, going to one- 
half in four days, according to Rutherford. 

According to 'the law for unconfined spaces, the activity 
induced should be almost imperceptible. Certain substances, as 
celluloid, paraffine, and caoutchouc, however, lose their acquired 
activity with great slowness, sometimes requiring fifteen or 

1. C. R. 136, 446, 671 (1903). 

2. C. R. 138, 411 (1904). 

3. Berichte 36, 2368 (1903). 
4- Thesis (1903). 


more days. In losing it, they also induce radio-activity. Doubt- 
less, this lag, or special induced activity, has much to do with 
the unique observations of Metzenbaum, 1 who caused zirconium 
and yttrium compounds to affect a sensitive photographic plate 
similarly to thorium compounds. His experience is unique and 
contrary to that reported by others. Perhaps it may be due to 
the admixture of small amounts of radium. This is the expla- 
nation he offers for the activity of thorium. Haitinger has 
extracted radium from commercial thorium oxide. 

Metzenbaum 2 produced skiagraphs with metallic aluminum 
by placing it directly on the sensitive gelatine. A shield of 
black paper or glass prevented the darkening of the plate. This 
can be readily attributed to chemical or electro-chemical action. 
He placed closed tubes of radium preparations in various pow- 
ders for several days. After removal, he obtained negative 
results as to induced activity, tested photographically and with 
the electroscope. 

Previously, much prominence was given by the secular 
press to the reports of exciting activity in salt and other solu- 
tions, which might be used internally for specific therapeutic 
effects. (See Chapter VI.) 

Heydweiller 3 reported no loss of weight from a closed 
radium tube. Dorn/ however, reported diminution, while 
Forch observed "no change. Davis, in our laboratory, was un- 
able to detect any loss in weight of a closed tube containing a 
gram of chloride, 7000 activity. So far no satisfactory experi- 
mental evidence, as to the loss of weight by radium compounds, 
has been offered. Piffard 5 calls attention to the fact that no 
authoritative statement has been given as to the rendering of 

1. "Radium, Radio-active Substances and Aluminum," Cleveland, 
O., '04. Scientific American, May 14,' 1904, and Cleveland Med. J., 
May, '04. 

2. Loc. cit. 

3- Phys. Zeit. 4, 81 (1902). 

4- Phys. Zeit. 4, 530 (1903). 

5- "A Few Words Concerning Radium," Medical Record. 


water or other substances radio-active by the presence of a 
closed tube of radium. He further detected defects in tubes, 
air bubbles, etc., and regards the statements concerning induced 
activity by means of closed tubes as based upon the use of 
defective tubes. As Curie and Rutherford have shown, induced 
activity requires a naked exposure of radio-active bodies. It is 
superficial, the real extent depending entirely upon the depth to 
which the emanations or their products have penetrated. It 
has bleen definitely proved that the emanations consist of mater- 
ial particles. Their expulsion and consequent transference, 
when radio-active substances are exposed, must, therefore, 
mean a corresponding loss in weight of the original substance. 

To explain the phenomenon of induced radio-activity, two 
hypotheses have been put forward. The first states that the 
inactive molecules of almost any substance after being mixed 
with an active substance like radium temporarily acquire the 
property of radio-activity. The second hypothesis states that 
inactive bodies become active by association with active sub- 
stances by removing a small portion of the latter, or by remov- 
ing a radio-active product of the element. Thus the excited 
activity may be permanent or temporary, decaying according 
to the law governing the radio-active product removed. From 
the work of von Lerch, already mentioned, the latter appears 
to be the most acceptable explanation. 



Naturally the ideas of Madame Curie, which led to the 
brilliant discovery, deserve first mention. Her experimental 
data warranted the assumption that racfio-activity is an atomic 
and not a molecular phenomenon, although she does not com- 
mit herself unreservedly to that explanation. 

Becquerel 1 used the following hypothesis for his investi- 
gations : radio-active matter, according to J. J. Thomson, con- 
sists of negatively and positively charged particles. As shown 
by Thomson's work, the negative particles have a mass of about 
i/iooo that of hydrogen, and the positive particles have a mass 
about equal to hydrogen. The former (or ^8- rays) are pro- 
jected at a very high velocity, while the latter are compara- 
tively sluggish, constituting the emanation which may be de- 
posited upon the surface of bodies and which give rise to 
exicted activity. 

Becquerel, 2 further, having noted that the activity of uran- 
ium was not constant, as previously noted by Giesel and 
Crookes, suggested that the emission of the deviable rays be 
identical with the cathode rays and the cause of the non- 
deviable radiation so much like the X-rays. It was thus com- 
parable to the evaporation of an odorous body. The dissipated 
energy would be given out from the active body itself, but the 
corresponding loss of weight would be too small to be observed. 

Rutherford and McClung 3 previously learned that the 
energy given out in the form of ionizing rays was 3000 gram- 
calories per year in radium, 100,000 activity, or with the pure 

1. C. R. 133, 979 (1901). 

2. C. R. 133, Dec. 9 (1901). 

3. Phil. Trans. 25 (1901). 


radium preparation, 1,500,000 activity, an emission of energy 
in the gas, as a-rays, of about 45,000 gram- calories per year. 
It was suggested that this energy might be derived from a 
re-grouping of the atomic constituents of radio-active elements. 
Even before that, Rutherford 1 believed that thorium emanations 
and excited activity were due to radio-active matters. With 
Brookes, and later Soddy, he learned that the emanations of 
thorium and radium behaved like gases, that they produced 
excited radio-activity, that they diffused through air like gases 
of heavy molecular weight, and that they behaved very much 
like the chemical inert gases, with the exception that they were 
dissolved in some acids and not in others. 

Curie 2 differed from Rutherford, calling attention to the 
fact that no spectroscopic evidence of the gas had been obtained 
and, that, also, the emanation disappeared when in a sealed 
vessel. He regarded the emanation as consisting of centres 
of condensed energy, attached to gas molecules, and moving 
with them. Rutherford 3 claimed that the failure to detect the 
gas spectroscopically could be accounted for through the mi- 
nute quantity of the emanation present (one gram of radium 
produces 3.3xio" 4 c. c. at atmosphere pressure and tempera- 
ture 4 ) although the electrical and phosphorescent actions were 
very marked with the amounts to be had: Rutherford and 
Soddy studied uranium, thorium and radium, condensed the 
radio-active emanations at the temperature of liquid air, demon- 
strated that the a-rays consisted of positively charged bodies, 
atomic in size, and projected with a great velocity. This proof 
of the materiality of the emanations forced upon them the 
necessity for assuming the continuous production, by thorium 
and radium, of new kinds of active matter which possess tem- 
porary activity and differ chemically from either of those two 

1. Phil. Mag., Jan. and Feb. (1900). 

2. C. R. 136, 223 (1903). 

3. Phil. Mag., April (1893). 

4. Phil. Mag., May (1903). 

5. Trans. Chem. Soc. 81, 321, 837 (1902), and Phil. Mag., Sept. and 
Nov. (1902), Feb., Apr. and May (1903). 


elements. Further, it was learned that the radio-activity as- 
sumes a constant, being a resultant equilibrium between the 
processes of production of active matter and the alteration of 
those already produced. 

Curie and Laborde 1 suggested that the heat may as well be 
supposed to come from the breaking up of the radium atom as 
from energy absorbed by it from some outside source. J. J. 
Thomson 2 postulated the emission of energy as being due to 
some internal changes in the atom, and that a large store of 
energy would be released by a contraction of the atom. 

Fillipo Re 3 put forward his belief that particles have pre- 
viously been free and that they constitute nebulous formations 
of extreme tenuity. In time they became reunited around 
centres of condensation, giving rise to small suns, as it were, 
which by ulterior contraction, take stable and definite form. 
These make up the atoms of ordinary chemical elements. As 
we know them, they may be compared to small extinct suns. 
The larger suns, not yet extinct or cold, constitute the atoms 
of radio-active bodies, hence the heat absorbed with these sub- 
stances. Latterly this idea has come forward with greater 

Hudson Maxim* accounted for its luminous, heat-giving 
effect by asserting that radium has a property opposite to ultra- 
violet rays, that the high electric waves impinging upon radio- 
active substances slow down to waves of lower pitch, some cor- 
responding with visible light, others with heat. In the same 
manner an opaque body like a piece of smoky glass, will get 
hot in the direct sunlight by a slowing down of the higher 
light rays to the lower pitch, which are sensed as heat. Two 
years later Lord Kelvin, in a paper before the British Associa- 
tion, presented the same theory, using nearly identical illustra- 

1. C. R. 136, 673 (1903). 

2. Nature (1903), 601. 

3. C. R. 136, 1393 (June 8, 1903). 

4. Electrical Are (1901). 


DuPont 1 suggests that radio-active substances are catalytic 
agents, radium being very powerful; that radio-activity is a 
form of catalysis, and that the action which radium has upon 
surrounding bodies is due to this cause. 

A catalytic agent is a body which by its mere presence 
accelerates chemical reaction or causes chemical reactions to 
take place within other bodies which would not react upon 
each other or would react very slowly, except for its presence. 
As an illustration, we may cite the action of platinum in the 
formation of sulphur trioxide from sulphur dioxide and 

The converse order was suggested, namely, that radio- 
activity might be used as a key to the solution of the problem 
of catalytic action. Radium has the effect of discharging elec- 
trically charged bodies. Riecke regards atoms as electrically 
charged. Perhaps the effects of radium upon animal tissue 
may be due to the discharging of negative electricity, which 
holds certain molecules from uniting with other molecules, 
thereby bringing about chemical reactions which under normal 
conditions are impossible of being effected. 

Attention is called to the phenomena observed within a 
spinthariscope. The emanations do not resemble light rays 
thrown off from luminescent bodies, but are more like a 
meteoric shower, or a lot of miniature bomb shells exploding. 
Maxim likens the action of radium to the familiar theory of 
the thunder storm. That is, small aqueous vesicles forming 
the clouds, each vesicle charged with a small amount of elec- 
tricity, unite with one another forming larger vesicles. As 
they are spherical* the larger vesicles show a smaller surface 
in proportion to the mass ; consequently the electrical tension 
upon the surfaces becomes greater as the vesicles grow into 
drops of water and it is the uniting into one great electrical 
spark of an infinite number of small electrical sparks passing 
from drop to drop that produces trie lightning flash and clap 

i. Scientific American Supplement, Apr. 9 (1904), P- 23631. 


of thunder. Radium, acting upon the atmosphere in contact 
with it, or in its immediate vicinity, discharges the electricity 
from certain molecules to certain other molecules, producing 
miniature reactions. Possibly these miniature electrical dis- 
charges produce light ; that is, one of these tiny flashes of light- 
ning. Were our ears acute enough it might be possible to 
distinguish these infinitely small claps of thunder. 

The production of helium from radium is attributable not 
to the conversion of any portion of the radium into helium, but 
to the production of helium from the atmosphere or other me- 
dium by the catalytic action of the radium. Therefore, the 
energy does not come from the radium, but exists in the atmos- 
phere as potential energy and is allowed by the radium to 
become kinetic energy, just as the platinum causes sulphur 
dioxide and oxygen at certain temperatures to combine, pro- 
ducing heat. 

From the observations made, Rutherford and Soddy 1 sug- 
gested that helium might be the production of the disintegra- 
tion of the radio-active elements. 

Gutton reported observations which, perhaps, have a bear- 
ing upon the theory of radio-activity. He found that when 
the lines of force of magnets are not parallel that luminous 
effects may be produced upon a phosphorescent screen, de 
Hemptinne, 2 ho'wever, was unable to verify the observations. 

Concerning the radio-activity of thorium, Baskerville 3 has 
called attention to the dividing of thorium into constituents 
which differ in their activity. Hofmann and Zerban 4 call at- 
tention to the important fact, from a chemical point of view, 
that thorium, which is radio-active, comes from minerals con- 
taining uranium. All the thorium preparations, with which 
physicists and chemists have usually worked, have, as a rule, 
come from complex minerals which, probably, contained varia- 
ble amounts of uranium. The above mentioned workers 

T. Phil. Mag. (1902), 582; (1903), 453, 579- 

2. C. R. 138, 754 

3. J. A. C. S. 26, 922. 

4- Berichte 35, 531, and 36, 3093. 


extracted from certain minerals, Norwegian gadolinite, yttro-ti- 
tanite, and orthite free from uranium, thorium which did not 
possess any radio-activity. Haitinger 1 has succeeded in extract- 
ing radium from thorium, which was prepared from Brazilian 
monazite sands. The writer and Zerban have later obtained 
a thorium preparation from a South American mineral, which 
is absolutely inactive. 

Fig. 45 

Boltwood's apparatus for showing the ratio of radium to uranium in 
minerals. A weighed quantity of powdered mineral is placed in bulb B. 
The acid to be used for decomposing the mineral is placed in C. After 
decomposition, which is brought about by inclining the tube so the acid 
may come into contact with the mineral, the apparatus is allowed to 
stand a few days until equilibrium is reached. The tube A is then sealed 
off at e. The air and radium emanation are then remove 1 from A by 
suction, introduced in an electroscope and the ionizing power determined. 

Boltwood 2 concluded from a determination of the amount 
of radium in radio-active ore, and the rate of leakage of the 
electroscope, that the amount of radium present stands in direct 
proportion to the percentage of uranium. 

1. Haitinger and Peters, Sitzungs Berichte (Wien) 113, May, 1904. 

2. Eng. and Min. Jo urn. 77, 756. 


It has been suggested by J. J. Thomson and Rutherford 
as very probable that radium is formed by the breaking down 
of the uranium atom. A final state of equilibrium and definite 
proportion between uranium and radium present in minerals 
was to be expected, which fact prompted Rutherford and 
Soddy 1 to suggest a complete study of the natural minerals. 
The improbability of any radium ore being found containing 
a greater portion of radium than pitchblende, because it con- 
tains the highest percentage of uranium, suggests itself. 

Preliminary experiments on the relative amounts of polo- 
nium present in two different uranium minerals, showed by 
comparison that in all probability this element also varies 
directly with the percentage of uranium present. 

Mendelejeff 2 insists that radio-activity indicates a 
material emanation. The arrival and departure of atoms are 
accompanied by disturbances which indicate waves of light. 

M. and Mme. Curie 3 have presented a general theory con- 
cerning radio-activity as follows : It is an atomic property. 
Each atom acts as a constant source of emission of energy, 
which may be derived directly from the potential energy of 
the atom, or the atom may serve as a means whereby the energy 
may be borrowed from the surrounding air. Crookes 4 sug- 
gested that radio-active elements possess the property of ab- 
stracting energy from a gas. That is, in order to account for 
the large emission of heat from radium noted by Curie and 
Laborde, the moving materials might strike a substance and 
be released with a changed lower velocity, a production of heat 

Lord Kelvin, 5 also, suggested that radium perhaps obtains 
its energy from an external source. It would Be interesting 

1. Phil. Mag. 576. 

2. "A Chemical Conception of the Ether," Longmans, Green & 
Co., '04. 

3. C. R. 134, 85, 1902. 

4. C. R. 128, 176 (1899). 

5. British Assoc., 1903 Meeting. 


to obtain inactive thorium and keep it for months in a vacuum 
and note whether or not the de-emanated body re-acquired its 

Many are not as yet ready to accept the materiality of the 
cathode or /2-rays. That the emanations are composed of defi- 
nite particles is proved beyond question. Most active products 
emit only a-ravs, or at least they constitute by far the major 
portion of the radiations. No substance has yet been obtained 
and known for any length of time which gives out only (3- 
or y-rays, either alone or together. Rutherford states that 
the ft- and y- rays in most cases appear only in the last stages 
of radio-active processes. This statement must be modified 
in view of the work reported by Rutherford at the Congress 
of Arts and Sciences, St. Louis, 1904. (See end of chapter.) 
Perhaps then in time those bodies which emit only a-rays may 
yield the other two forms of recognized energy. Such falls 
in well with the theory proposed by the writer 1 and Lockhart, 
which follows : 

The elements of high atomic weight are electro-positive. 
The emanation particles bearing a positive charge are repelled. 
As they are lighter and gaseous, they are thrown away from 
the ponderous solids at a high velocity, about i/io that of light. 
These particles provoke an opposite charge producing ethereal 
stresses, cathode or /3-rays. These acting upon any solid sub- 
stance produce the y-rays in the same manner that the Rontgen 
rays are produced without the Crookes tube through the influ- 
ence of the cathode rays within. This 'appears to negate en- 
tirely the postulates of Crookes and J. J. Thomson as to the 
materiality of the cathode rays. It is maintained by some that 
while the presence of material particles may be accepted, they 
are the remnants of gas not removed in the exhaustion of the 
tubes. In fact the efficient modern Crookes tubes for the pro- 
duction of X-rays are arranged to keep a variable amount of 
gas present within. The gas particles serve as carriers of the 

i. "The Cause of Radio- Activity," Washington Section A. C. S., , 
April 6, 1904. 


negative charge and the assumption of the materiality of the 
cathode or j3- rays becomes unnecessary. 

J. A. McLennan 1 stated that the emanation from radium 
is not charged electrically. The radium atom gives off posi- 
tively charged particles. "The emanation cannot be what 
remains of the atom after the emission of these rays, as it 
would then be negatively charged. The atom must have, 
therefore, parted with an equal negative charge, either by the 
emission of negative particles or in some other way." 

Schenck 2 proposed a theory for radio-activity based on the 
hypothesis of electrons in phenomena of chemical equilibrium 
and more particularly in that one between oxygen and ozone 
which is controlled by the laws of mass effects. 

Richartz has shown that ozone belongs to the group of 
radio-active substances and on being dissociated will become 
a conductor of electricity. In short, it would be converted 
into oxygen while giving off gaseous ions. On the other hand, 
its formation takes place whenever in certain electric phenom- 
ena gaseous ions are present and a reversible process analo- 
gous to the dissociation phenomenon occurs. If gaseous ions 
be considered as material particles, the ozone may be regarded 
as a chemical compound of electrons and oxygen, or an "elec- 
tronide" of oxygen. Both electrons of atomical ions would be 
controlled by the mass law in the same way as electrolytic ions 
and electrical and neutral molecules. The hypothesis is sug- 
gested that radium and analogous substances might also be 
"electronides." The process might be analogous to the dis- 
sociation of calcium carbonate into calcium oxide and carbon 
dioxide. Probably radio-active substances should be produced 
by volcanic phenomena, as they are attended by violent evolu- 
tion of electricity. In many slow reactions giving rise to the 
formation of ozone, the presence of gaseous ions has lately 
been ascertained. It is probable that many, if not all, reac- 
tions are attended with the presence of such gaseous ions in 

1. Phil. Mag. 6, 7, 355 (1904). 

2. Pruss. Acad. of Science (1904). 


variable quantities. On the other hand, hydrogen dioxide is 
analogous to ozone, giving off so-called emanations which 
do not influence photographic plates through a sheet of alumi- 
num. It should equally be considered as an electronide. In 
order to produce a luminous sensation on the eye, the concen- 
tration of ions should apparently exceed a certain limit. 
Schenck enunciates the hypothesis that emanations of radio- 
active substances are nothing else than ozone. An attempt was 
made to account for excited radio-activity by the action of 

Winkler 1 took a rather radical position, insisting that all 
of the reported radio-active elements simply contain a varia- 
ble amount of radium, and furthermore he intimated that 
radium itself is not an element but that it may be impure stron- 
tium with an excessive electrical charge. 

Davis, 2 in endeavoring to decide between the two hypoth- 
eses to explain radio-activity namely, "Atomic Degradation" 
and "Molecular Change" (Armstrong and Lowry, Proc. Roy, 
Soc., 1903) found that metallic selenium affected the photo- 
graphic plate through black paper. Similar results have been 
reported by Taudin and Chabot. 3 

McCoy 4 discussed the decomposition of radium from the 
standpoint of the law of mass. The order of decomposition 
was considered as follows : 

Ur x Ur-X x Ra x RaEm x Em-X x He. 
The radio-activity of an ore would be in proportion to all of 
these, but may be judged by the amount of uranium present, 
as was pointed out by Boltwood. 3 

Before giving the theories of those who have done most, 
experimentally, (Rutherford and his co-workers), toward an 

1. Berichte 37, 1655 (1904)- 

2. Nature 70, 506 (1904). 

3. Phys. Zeit, Aug. 25 (1904)- 

4. Berichte 37, 2641 (1904). 

5. Am. J. Sci. 1 8, 97 (1904). 


elucidation of the difficult problem, it is appropriate to mention 
several interesting facts bearing upon the subject. 

In 1895, Perrin, 1 as did J. J. Thomson, 2 two years later, 
offered proof that the Crookes's rays consist of negatively 
electrified material particles. Omitting the mathematical calcu- 
lations, it may be said that these particles carrying a unit charge 
are one ten-thousandth of a milligram'' in mass. Thomson 
proved that the electric charge on a particle in case of gaseous 
electrolysis is the same as that of a hydrogen atom in liquid 
electrolysis; namely, 1.13 X io" 20 , E. M. U. and since the mass 
of hydrogen required to carry a unit charge, in the case of 
ordinary electrolysis, is one-tenth of a milligram, it follows 
that the mass of cathode particles required to carry a unit 
charge can be only one-thousandth as great. Therefore, the 
masses of these electro-negative particles constituting the cath- 
ode rays are one-thousandth of a mass of a hydrogen atom. 
The accepted value of the mass of a hydrogen atom is 2.3 X 
io" 21 , the mass of the cathode particles is 2.3 X io" 24 , milli- 
grams. Thomson also determined the speed of the par- 
ticles as being from 2.2 to 3.6 X io 9 c.m. per second. The 
speed of light is 3 X io 10 c.m. per second. Hence the cathode 
rays have a velocity of one-tenth of that of light. These veloc- 
ities vary somewhat in different experiments, the highest value 
obtained being about two-fifths the speed of light. Thomson 
called the particles "corpuscles," as his ideas resembled New- 
ton's corpuscular theory. In fact, Thomson suggests that they 
constitute negative electricity, which is a return to the single 
electric fluid theory of Franklin. 4 

The energy of the corpuscles is enormous. Although 
they are minute, the energy effect is considerable. * It has been 
estimated that the energy emitted from each square centimeter 

1. Compt. Rend. 121, 1130. 

2. Phil. Mag. V, 44, 293. 

3. Phil. Mag. V, 48, 547 (1898). 

4- Harper's Magazine, 103, 64, Sept. (1901). 



of radium would melt a layer of ice of the same area and one- 
quarter of a mile thick in a million years. Or, as Lord Kelvin 
has said, the emission of matter and corresponding- loss of 
energy have apparently been going on indefinitely in the past. 
As he says, it appears to place the first question mark after 
the great fundamental law of the conservation of energy. 

Strutt devised an instrument which gives the nearest ap- 
proximation to perpetual motion so far observed. The descrip- 
tion of a radium clock as constructed by Mr. Harrison Mar- 
tindale of England is given as illustrative of the principle of 
Strutt's apparatus. The registration of time is made in two- 
minute beats. The function of the apparatus is to exhibit the 
dissipation of negatively charged a- and /3-rays by radium. 
A small tube containing a minute quantity of radium is sup- 
ported in an exhausted glass vessel by a quartz rod. To the 
lower end of the tube is attached an electroscope formed by 
two strips of silver foil. The leaves diverge, striking the walls 

Fig. 46. 

Strutt's Radium Clock. It has been suggested that a very reliable 
time-piece may be constructed on this principle. So far however no 
satisfactory method of mechanically registering the charging and dis- 
charging, that is, beats, has been devised. 


of the vessel, which are grounded by wires, and are discharged. 
The operation is repeated incessantly requiring two minutes. 
In this instance it is calculated that it will take 30,000 years 
until the radium is exhausted. 

The speed with which the corpuscles move from the radio- 
active substances is even greater than that of Crookes's rays, 
Becquerel has shown that their speed may be as high as two- 
thirds that of light. Other investigators have obtained even 
higher velocities, 2.8 X io' c.m., having been measured. The 
rays emitted by radio-active substances consist in part at least 
of material particles having a high velocity. Therefore, a loss 
of matter must go on continuously. Madame Curie estimates 
that radium emits from each square centimeter of surface 1.2 
milligrams of matter in one million years. Therefore, it would 
be impossible to observe, by the most delicate balances at pres- 
ent available, any loss in mass during two million years. 

Two important questions present themselves to the reader 
if these statements even approximate the truth. Where does 
this radium and radio-activity come from? and what is its real 
influence in the world ? 

W. E. Wilson, 1 Darwin 2 and Joly 3 independently suggested 
that radium might enter as an important factor in contributing 
to solar radiation and the maintenance of solar temperature. 
Reference has already been made to Rutherford's belief that the 
amount of radium present and uniformly distributed through- 
out the earth would be sufficient to account for its loss of heat. 
Thus it will be seen that .the life of the earth has continued 
sufficiently long to allow the time necessary for the processes of 
evolution of the geologists and biologists. 

Thomson, at a recent meeting of the British* Association, 
as a result of his experiments on the universal distribution of 
radio-activity, concluded that each metal gives out a specific 
radiation which differs in its properties from the radiations sent 

1. Nature, July 9 (1903). 

2. Nature, Sept. 24 (1903). 

3. Nature, Oct. i (1903). 


out by any other substance, and appears not to be a secondary 
radiation due to contact with some other form of radiation 
present in the atmosphere. 

So far no satisfactory experimental evidence has been 
offered to prove that the energy of radium is derived from 
external sources. Yet the following idea gave the writer 
momentary comfort. An insulated wire formed into a circle, 
the ends free, horizontal, vertical, or inclined as far as the 
earth's surface is concerned, is perfectly neutral. Let it be 
revolved and an electric current is produced. Evidences of 
energy are had. Vary the speed and number of circles and 
differences in the current are observed. 

Is it too great a draught upon the imagination to think 
that the atoms which are heaviest possess this same power? 
Their motion, perhaps on account of their weight, is such as 
converts the earth's lines of force into perceptible energy. 
The Curies early made a suggestion somewhat similar to this; 
namely, that radium might have the power of absorbing a 
species of Rontgen rays from the earth and converting them 
into other forms of energy. It has been shown that there is 
in fact a kind of penetrating rays, like the y-rays of radium, 
near the earth's surface. The writer's dream was dissipated 
by rinding a heavy constituent, inactive thorium. It comes 
back now, since Rutherford has shown that during the disin- 
tegration of the emanation a temporary inactive state is arrived 

So substances may vary in the amount of their activity, 
as shown for radium and thorium preparations. Fresh radium 
requires time to reach its maximum. So does thorium, while 
Rutherford's thorium-X runs down to a minimum, which 
is the maximum of its mother substance. In one case it re- 
quires time to reach the stable speed. In the other, it requires 
time to slow down to the safe equilibrium rate. The dynamo 
analogy becomes more perfect when we have active and inac- 
tive thorium. 


J. A. Alexander 1 insists that radio-activity is due to exter- 
nal energy. He says : 

"All matter, as we know, is continually receiving and 
giving out energy but the total sum of the plus and the minus 
in the universe equals zero. 

Radio-activity and magnetism are in some respects anal- 
ogous. Each is exhibited most strongly by one element, and 
to a lesser degree by several closely allied elements. Each can 
be communicated to some other bodies without apparent loss 
to the original active substance. Both are impaired by heat, 
fusion or solution, which seem to alter the conditions of the 
molecular complexes. We believe magnetism to be consequent 
upon the localization of ever-existent cosmic forces ; and it 
seems to be probable that radio-activity can be traced to the 
same origin." 

Rutherford and Soddy, assuming that radio-activity is an 
atomic and not a molecular property, advance the most accept- 
able theory yet put forward ; namely, the atoms of radio-active 
elements undergo spontaneous disintegration. This takes 
place in fixed and well-marked steps. These changes are 
nearly always accompanied by the emission of a- rays. 

The emission of the radiations is dependent solely upon 
the amount of active element present. The rate of emission is 
not affected by- variations in temperature or by any known 
chemical or physical forces. It has been demonstrated that 
the radiations consist for the most part of positively and nega- 
tively charged particles, projected with great velocity. Hence 
it has been assumed that part of the atoms escape from the 
atomic system. It is difficult to imagine that the projected 
particles can suddenly acquire such a velocity of movement 
through the action of force, either within or without the atom. 
To illustrate this point, attention may be called to the fact 
that the a particles, according. to Rutherford, ''would have to 
travel from rest between two points, differing in potential 5.2 
million volts, in order to acquire the kinetic energy with which 

i. American Chem. Society (N. Y. Sect.), Nov. n, 1904. 



it escapes. They must, therefore, escape from a system which 
is already in exceedingly rapid motion. Consequently, the 
energy exists before hand in the atoms from which they 

J. J. Thomson, Larmor and Lorentz have urged the con- 
ception that the atom is very complicated, being made up of 
charged particles, in rapid oscillatory or orbital motion. As 
the particle is atomic in size, it must be composed of electrons 
in motion. The radio-active elements, therefore, are composed 
of positively charged particles, whose mass is about that of 
hydrogen or helium. 





The curves (see Fig. 47), showing the decay of the activ- 
ity of the emanation and the recovery of the activity of radium 
are extremely interesting. It will be noted that they are com- 
plementary to each other. When the emanation has lost one- 
half of its activity, the radium has spontaneously regained one- 
half of its lost activity. The sum of the three factors, namely 
the activity from the separated emanation, the activity of the 
remaining radium, and that lost, constitute a constant. This 


is accounted for by assuming that radium is always manufac- 
turing fresh emanations at a definite rate. When the emana- 
tion is removed, the radium is temporarily exhausted but imme- 
diately proceeds to produce more emanation and store it up. 
As these two reach an equilibrium, we have the constant activ- 
ity of the radium. 

The laws which control the material a and /? particles 
are different from those of ordinary chemical changes. Tem- 
perature, which plays an important part with all ordinary 
chemical reactions, has no noticeable effect in changing the 
processes occurring in radium, as already referred to. The 
rate of decay of the activity of the emanation is apparently 
not changed by severe physical and chemical treatment. As- 
suming that changes occur within the atom, we should expect 
temperature to have little influence, for we know from our 
experience with different elements that wide variations in tem- 
perature have little effect in altering stability. During this 
process of disintegration at least five distinct substances are 
produced. The emanation is, chemically, an inert gas, while 
the other products act like metallic substances soluble in some 
acids and volatilized by heat. Each of these different sub- 
stances is different from an ordinary chemical element, because 
it is not permanent and is continuously and rapidly changed 
into another kind of material. This is shown graphically by 
Rutherford in the accompanying diagram (Fig 48). Ruth- 
^.erford gives a very interesting table showing the time required 
for the different changes. 




Name of Substance 






4 days 

Jst product 


Emanation X (ist change) 

3 minutes 

2nd product 


Emanation X (2nd change 

21 minutes 

3rd product 


Emanation X (3rd change) 

28 minutes 

4th product 


Emanation X (4th change) 

very slow 

5th product 


In each case, but one, the transformation is accompanied 
by the throwing out of a particles and in one only, namely 
the fourth stage, are evidences of ft- and y-rays obtained. Some 
evidence is already had which indicates that radio-tellurium is 
really the fifth product of the disintegration of the radium atom. 

Each one of these chemical products has distinct chemical 
properties, which distinguish it, not only from its immediate 
neighbors but from the parent element and the final product. 

It has been calculated that the weight of the emanation 
obtained within four days from one gram of radium bromide 
is about i/ioo of a milligram, while the weight of the fourth 
product, which breaks up in twenty-eight minutes, is about 
3/100,000 of a milligram. This amount is entirely too small 
to be detected by balances, so it can scarcely be hoped that 
enough of it can ever be collected, in sufficient quantity, on 
account of its limited life. The inactive products, however, 
will continue to increase as long as there is any of the mother 
element present. This is really an apparent case of the trans- 
mutation of the elements. 

Truly, as Runge says, "Nature is becoming more and more 
disorderly every day." 

In the author's humble opinion we are not yet warranted 
in accepting this as the correct solution of the problem, beauti- 
ful as the explanation is. So far, however, nothing better has 
been offered and, as with all things in science, it should be 
accepted until something better takes its place. 


Ramsay 1 states that electrons are not matter but are capa- 
ble of causing profound changes in matter. For a year a solu- 
tion of radium bromide was kept in three glass bulbs, each 
bulb connected to a Topler pump by means of capillary tubing. 
This was done to collect e.v-radio, the term he proposed for 
"emanation-substance." Each of the bulbs, to avoid accident, 
was surrounded by a small beaker, one consisting of potash 
glass and the other two of soda. The potash beaker became 
brown, while the two soda beakers became purple. This varia- 
tion in the color was attributed to the probable liberation of the 
metals potassium and sodium, which ordinarily exist in that 
very viscous liquid, glass, in the colorless ionic state. The glass 
had not been subjected to the a-rays, therefore, to no bombard- 
ment of what is usually called matter except the molecules of the 
surrounding air. The colored beakers are radio-active and 
the radio-active film dissolves in water. After careful washing 
the glass was no longer radio-active. The solution contained 
an emanation, for in bubbling air through it and cooling the 
issuing gas to 180 C, part of the radio-active matter was 
retained in the cooled tube. This air, also, discharged an elec- 
troscope. The period of decay was very rapid. In having 
such a short period of existence the emanation resembles that 
of actinium. The water solution on evaporation gave a resi- 
due which was strongly active. On adding mercurous nitrate 
to the dissolved residue and then adding hydrochloric acid 
the greater part of the active matter was thrown down with 
the mercurous chloride. This appears to indicate the forma- 
tion of an insoluble chloride. The activity of the mercurous 
chloride remained unchanged for ten days. The filtrate from 
the mercurous chloride was active. On precipitation the mer- 
curous sulphide was also active but its activity decayed in one 
day. The filtrate from that gave an inactive precipitate with 
ammonium hydroxide, hence the active matter forms an insol- 
uble chloride and sulphide. These, when dissolved in aqua 

i. "Present Problems of Inorganic Chemistry," address before the 
International Congress of Arts and Science, St. Louis, 1904. 


regia, gave an insoluble sulphate when barium chloride and 
sulphuric acid were added. This indicates the formation of 
an insoluble sulphate, that is a body somewhat resembling lead. 
The explanation given for this was perhaps misinterpreted by 
the secular press into the actual building up of elements ; in 
short, a verification of the dream of the Alchemists, although 
Ramsay gave as his "guess" that such an explanation was more 
than likely. 

Without doubt the most valuable of the recent work on 
the "Transformation Products of Radium" was that reported 
by Rutherford 1 at the International Congress at St. Louis. He 
studied the residual activity of a bismuth rod exposed to the 
emanations of radium. The residual activity consists of both 
a- and /3-rays, the latter being present in unusually large pro- 
portion. He, also, noted the proportion of the a- to (3- rays- 
from a platinum plate one month after removal from exposure- 
to the emanations. Unlike the a- rays activity, the activity meas- 
ured by the ft- rays remains constant, consequently the propor- 
tion of the a- to the (3- rays steadily increases. The intensity 
of the /8-rays did not vary much over a period of nine months. 
This want of proportionality between the a- and /3-rays shows 
that the two types arise from different products. The activity 
deposited apparently consists of two kinds of matter: (i) a 
product giving only /8-rays which is soluble in sulphuric acid 
but not volatile at 1000 and which is not deposited on bismuth ; 
and (2) a product giving out only a- rays which is soluble in 
sulphuric acid, volatile at 1000, and is deposited from a solu- 
tion on bismuth. 

The a- ray activity increases if the ft- ray product is pres- 
ent. It remains sensibly constant, or generally very slow in 
decay, if the a- ray product is removed from the /8-ray product 
by the action of the bismuth plate. The /3-ray activity remains 
sensibly constant independent of the presence of the a- rays. 
These results show that the /3-ray product is the parent of the 
a- ray product. The amount of residual activity from radium 

i. Phil. Mag. 8, 636 (1904). 








Fig. 49. A graphic comparison of the a and /? particles. The velocity is 
represented by the length of a line and the mass and energy by spheres. 

emanations depends upon the amount of the emanation present 
and the time of exposure to the emanation. Rutherford has 
changed his nomenclature and illustrates graphically the 
change, as shown in Fig. 50. By such an explanation he is 
able to account for the presence of radium-D and radium-E 
in pitchblende. He doubts if radium-D has been separated 
from pitchblende, although it is barely possible that the radio- 
lead of Hofmann, which emits a large amount of /?-rays, may 
be radium-D. Concerning radium-E, he thinks there is little 
doubt that it is the radio-tellurium of Marckwald, as his active 
bismuth gave out only a-rays. Rutherford states that it will 
be of extreme scientific value if the radium-D can be had from 
pitchblende, as it could be used for many of the purposes of 
radium. Its activity is about 25 times that of radium and the 
rate of change in the activity is sufficiently slow to be negligi- 
ble for most experiments. 



Active Deposit 

Ropid Change 

Fig- 50 

Active Deposit 
Slow Change 

Diagrammatic representation of the changes occurring in radium and 
its emanations according to Rutherford [Phil., Mag. 8, 641 (1904).] 





From what we have learned in the preceding chapter as 
to the resemblances among the radium and other rays, it is 
not unreasonable to anticipate specific physiological effects 
from the radio-active substances. That this is true, however, 
was accidentally and painfully discovered previous to the 
observation of WalkhofP that radium rays inflame the skin 
similar to the Rontgen rays. 

Becquerel carried a small tube of an impure radium prep- 
aration in~his vest pocket for six hours. A few days later he 
observed a reddening of the epidermis of the abdomen opposite 
the location of the pocket in which he had placed the radium 
compound. It was not long before the inflammation became 
pronounced, and an ulcer developed which required several 
months for the healing. 

Giesel 2 exposed the inner portion of his arm, for two 
hours, to 0.27 gram of a radium preparation, enclosed with a 
double celluloid capsule. After two or three weeks the skin 
reddened, blisters formed and the epidermis peeled just as with 
a burn. The growth of hair was also destroyed and did not 
come out anew, although a smooth white skin reformed. These 
observations were verified by Becquerel and Curie. "The 
action of radium upon the skin can take place across metal 
screens, but with weakened effect." 3 (Fig. 51.) 

1. Photogr. Rundschau, Oct., 1900. 

2. Ber. d. deutsch chem. Ges. 33, 3570 (1901). 

3. Madame Curie's Thesis. 


Fig- 51- 

Professor Curie's arm, showing a scar resulting from a radium 
sore. (Through the courtesy of the Success Company.) 

Rehns studied the precise effect of radium burning upon 
the skin. The rays from twenty milligrams produced no pain 
and left no mark at the time of the application. A red mark 
appeared 24 hours later, remaining for two weeks and then 
fading away, leaving a scar similar to a burn. If the applica- 
tion be continued for ten minutes the mark becomes visible 
in 1 8 hours, but ulceration does not occur unless the radium 
has been applied for at least an hour. If the burned spot be 
treated medicinally the wound may be cured in six weeks, but 
if not attended to, it ulcerates, becomes painful and the ulcer- 
ation lasts for an indefinite period. 

* Moles can be destroyed by the application of radium for 
ten minutes. 

i Abbe 1 appears to have been the first to record the fact that 
an ordinary wart (verruca vulgaris) is caused to disappear by 
the application of radium. The age of the growth seems to 
have no influence. Within three or four days a pink zone 
appears around the base of the growth, then it begins to flatten 
and usually disappears inside of ten days, leaving a smooth 

Giesel observed the action of radium upon plant growth, 
noting that the leaves treated turned yellow and withered 
away. He, also, discovered the action of radium upon the 
eye. If a radio-active substance be placed near the eye or 

i. Medical Record, 66, 321 (1004). 


temple, when the person is in the dark, a sensation of light 
is experienced. On the announcement of these observations 
the secular press hailed a cure for blindness. Heinstadt and 
Nagel and Crzellitzer, however, have studied the phenomena 
carefully and demonstrated that the centre of the eye is ren- 
dered fluorescent by the action of the radium. This gives 
the sensation of light experienced. 

The effect upon the eyes produced by radium is a diffuse 
brightness, somewhat like that one experiences when he steps 
from a dark to a brilliantly lighted room, with the eyes slightly 
closed, that is, the interior of the eye begins to fluoresce. The 
cornea, the lens, especially the vitreous humor, and perhaps 
the retina are involved. This is quite different from the 
effect of Rontgen rays, which act upon the retina alone. A 
pure radium salt acts with such intensity that the effect may 
be obtained by placing the chemical back of the head, and 
without the intervention of the optical apparatus at all. The 
Becquerel rays may produce an apparition, but it is not pos- 
sible to secure a picture as they are deficient in a characteristic 
property of visible light, namely, refraction.* 

Concerning the statement that totally blind persons are not 
only able to see the radium light, but perceive the phosphor- 
escent radium screen and distinguish silhouettes, coins, keys, 
etc., placed on the screen, Halzknecht and Schwarz 2 offered 
two explanations. The radium rays passing through the tis- 
sues reach and irritate the optic nerve and stimulate the relics 
of visual capacity left in it. In this case the nerve would 
also experience the same tendency. The blind person, after 
a little practice, should be able to perceive any dark object 
on a bright background. Heller, having made some experi- 
ments along this line, found it possible and that the same 
results could be obtained by any light. The radium had 

1. See Karewski in Marckwald's "Uber Becquerelstrahlen und 
radio-active Substanzen," Moderne Arztliche Bibliothek, Heft 7, Berlin 

2. "Ueber Radium-strahlen," Wien Klin. Wochenschrift 16, 25. 


nothing specific to do with the phenomenon. The other and 
perhaps the correct explanation, is based upon the transforma- 
tion of the energy of the radium rays into objective phosphor- 
escence. Animal tissue, hair, bone, muscle, drops of water, 
etc., are rendered more or less vividly phosphorescent under 
the action of the radium rays. The radium rays render the 
sclerotic phosphorescent and this phosphorescence is seen by 
the point of the retina opposite to it. When a visual sensation 
is experienced from compression of the eye-ball, the source 
of the light is referred to the point opposite to that from 
which the compression light proceeds. This is the reverse of 
the experience with radium. 

There is no doubt but that blind people whose retinas are 
intact are sensitive to the action of radium, but those with 
diseased retina experience absolutely no luminous sensation. 
London, in St. Petersburg, aroused many hopes by his observa- 
tions, but GreefF, in Berlin, on extending the experiments, 
came to the same conclusions given above. 

Javal 1 has suggested that blindness with alteration of the 
retina can be distinguished from that due to glaucoma or 
cornea! opacity, because patients with the latter condition see 
radium rays as well as do those of sound vision. 

Rollins 2 suggested the use of radio-active substances as 
a substitute for "the X-light. He prepared a capsule, with an 
aluminum front and back of comparatively non-radiable metal 
hich could be worn over a lupus or superficial cancer. 

Danlos 3 of the St'. Louis Hospital, Paris, apparently was 
the first to apply radium in the treatment of certain affections 
of the skin similar to the treatment with Rontgen and the 
ultra-violet rays (Finsen). A case of lupus of the face was 

1. Revue Internationale d'Electrotherapie et de Radiotherapie, Nov. 
and Dec., 1902. 

2. Medical News, Jan. 25 (1902). 

3. Revue 1'Electrotherapie et Radiotherapie, Nov. and Dec. (1902). 
Ann de Dermatologie et de Syphilis, July (1902). 


treated with radium chloride (iQOOoX). The disease disap- 
peared with the formation of a smooth white cicatrix, blending 
into the surrounding tissue. 

Fig. 52. 

Dr. Danlos and assistants treating a lupus patient with radium. 
(By courtesy of the Success Company.) 

Hallopeau and Gadaud 1 report that too prolonged applica- 
tion of radium led to atonic ulceration which lasted for five 
or six months ; also, that ulcers of normal tissue can be avoided 
by proper technique and care. 

Blandamaur has also used radium in lupus. 

Danycz 2 found that radium destroys the skin of guinea pigs 
and rabbits ; but subcutaneous and muscular tissue do not seem 
so sensitive as skin. Nervous tissue is sensitive to its action. 
A glass tube containing a radium salt, which was placed against 
the skin over the spine, produced death in young animals. In 
older animals, the osseous tissue seems to protect the cord 

1. Ibid. 

2. Compt. Rend. 136, 461 (1903). 


against the radiations. Danycz and Bohm showed that various 
larvae and embryos are profoundly modified in their growth, 
many being killed, when subjected to the radiations; others 
developing into monstrosities, because of unequal stimulation. 
The latter 1 observer found that the radiations exercise an espec- 
ially intense action on tissues and cells in proliferation. Non- 
fertilized eggs may undergo more or less parthenogenetic de- 
velopment and give rise to atypical formation. In the case 
of some animals, where the skin has been burned by the rays, 
the hair appears to be forced into rapid growth. It seems that 
various effects are obtainable, depending on the tissue or cell 
exposed, as well as on the quantity and quality of the rays. 

When two groups of meal worms were placed in jars, oveV 
one of which radium was suspended, many of the radiumized 
worms died ; those which lived showed much retardation. The 
worms in the 'parallel jar passed through the regular cycle of 
life, laid eggs which grew to worms, and repeated the cycle 
three or four generations. The radiumized worms still 
remained mere worms. 

B6hm v reported, as a result of experiments, that lower 
organisms are quickly destroyed by radium rays. 

Tur exposed eggs, for 24 to 70 hours, to the action of a 
35 per cent, radium chloride. The central parts were partic- 
ularly affected, t-he surrounding blastoderms remaining un- 
touched. Aside from numerous variations in the embryonic 
skeleton, there was a peculiar vascular formation in the centre 
of the embryo and other phenomena, showing a peculiar local- 
ization of the injurious radio-active effects. 

Holzknecht 3 reported psoriasis and lupus hypertrophicus 
as cured by both X-rays arid radium. The radium was superior, 
if anything. Epithelioma of the cheek also rapidly sub- 
sided. Apparently the healthy skin in the neighborhood of 

1. Compt. Rend. 136, 1016 and 1085. 

2. Soc Biol 55, 1655. 

3. Wirkung der Radiumstrahlung bei Hautkrauheiten, Vienna Klin 
Wochenschrift, 16, 27 (1903). 


these affections is not seriously interfered with. Radium 
seems to produce degenerative processes in the cells of the 
intima of the blood vessels, shown by Scholtz, as character- 
istic of the Rontgen rays. On account of the degeneration, 
there ensues a rapid dilatation of the capillary and precapillary 
vessels. These observations were made upon a remarkable 
case of telangiectesis. 

A committee appointed by the Vienna Academy of Science 
to investigate the results of the treatment of cancer with 
radium, reported, says the Popular Science Monthly, "in nine 
cases in which the treatment was used abatement in the can- 
cerous swelling resulted, and in two of these cases the swelling 
had not reappeared after five months' time. A case of cancer 
of the palate was much improved by the treatment. The use 
of radium is not recommended when an operation is practica- 
ble." Numerous other cases of the beneficial results of the 
radium treatment have been reported. The press reports from 
the London Cancer Hospital do not appear to be so encour- 

Exner 1 applied a capsule containing a cadium preparation 
by fastening it to the spot with adhesive plaster. The nodules 
following an operated melano-sarcoma disappeared when 
treated twenty-five minutes with the radium. They disap- 
peared before the superficial tissues exhibited necrosis from 
the action of the rays. A capsule containing radium bromide, 
protected from moisture by a rubber cot, was applied to a case 
of epithelioma, at the corner of the mouth, six times within 
seventeen days. The tumor perceptibly diminished, the ulcer 
began to heal over ; at the end of the month it had apparently 
vanished. This physician also reports on the radium treat- 
ment of six cases of carcinoma of the oesophagus. 2 

The technique was the introduction of a scrap of radium 
embedded in dammar, and fastened to a No. 16 sound. The 

1. Radium Treatment of Malignant Tumors and Cutaneous Affec- 
tions; Vienna Klin Wochenschrift 16, 27 (1903)- 

2. Semaine Medicale. Paris, 24, 9 (1904). 



increased permeability of the structure noted in the five cases 
was probably due to necrosis of the structure tissue under the 
influence of the radium, thus giving permanent results. 

Morton 1 favors radiation to* operation in the treatment of 
malignant disease in its earlier stages. Robert Abbe 2 sum- 
marized his wide experience with radium in the treatment of 


, \m/.--. 



Figs. 53 and 54. 

Method of applying radium preparations in local treatment accord- 
ing to Morton. 

lupus, epithelioma, rodent ulcer and carcinoma, by saying "lupus 
can usually be cured by a few applications of radium, varying in 
number, and frequently with the strength of the specimen. 
Superficial epithelioma, rodent ulcer, and small recurrent can- 
cer nodules, can be caused to disappear by cautio'us applica- 
tion, but if mild preparations are used, very little effect is seen. 
Indeed, the judicious use of Rontgen rays is more efficient 
along the same line in results and with only brief applications." 

1. "Treatment of Cancer by the X-rays with Remarks on the Use 
of Radium;" International Journ. of Surgery, New York, Oct. (1903). 

2. Yale Medical Journal, June (1904). 



Fig- 55- 

Apparatus of Williams, Brown & Earle, used in applying radium 
compounds in medicine. 

Seventy-five milligrams of radium, in a mica-covered box, 
were bound to Goldberg's 1 arm for three hours. Four days 
later a red patch developed, changed into a necrotic ulcer on 
the fourteenth day, and other ulcers developed on different 
parts of the arm; also, on the skin, in the groin and hand. 
The healing processes commenced first in the later patches. 
The ulcers were slow but sure in the healing. The action of 
the radium was probably due to its activity and not to its bulk. 
The exposure and the subsequent phenomena were painless. 
The necrosis developed without fever, and the ulcer had a 
peculiar morbid character. Rodent ulcers were cured. 

Cleaves 2 reports the cure of several cases of recurrent 
epithelioma of the rodent ulcer type. 

Williams, who has carried out most systematic investiga- 
tions on the medicinal applications of radium compounds, calls 

1. "Zur Frage der Beziehungen zwischen Becquerelstrahlen., und 
Hautaffektionen," Goldberg and London, Dermatologische Zeitschrift, 
Berlin, 10, 5 (1904). 

2. i3th Ann. Meet. Amer. Electro-Therap. Assoc., Atlantic City, 
Sept. 24, 1903. 


attention to the fact that radium possesses less value in diag- 
nosis than X-rays, as it does not differentiate so clearly. He 

Figs 56 and 57. 

The simple technique of applying radium compounds in the treat- 
ment of skin diseases. 

employed it as a therapeutic agent in nine cases of skin affec- 
tions, two of eczerna, and psoriasis, four of lupus vulgaris, and 
one of acne. Success was not so good in eczema, although 
there was some improvement. In lupus, the results were sat- 
isfactory ; also with acne. This important paper has reference 
to other work, which treats of thirty-three cases which show 
that radium is useful in treating some skin diseases and super- 
ficial new growths, including in this class those of the cervix 
uteri. He endeavored to differentiate as to the value of the 
different rays by isolating the ft and y rays. The burning 
power he attributes to the /3 rather than the y rays. As a 
result of his large experience, he regards the therapeutic ac- 
tion of radium as being of greater value than the X-rays, ex- 
cepting that the latter is able to cover larger areas. He con- 
cludes as follows : "If the results obtained by radium prove 




Fig. 58 

Lieber's Aluminum Tube for containing Radium. 
A. Aluminum tube containing radium, which is closed hermetically 

B. a wedge fitted with a screw thread so that 

C. a lid may be screwed on same, thereby closing the tube her- 
metically. This must not be opened after the radium has 
been filled in. 

The lid C has a screw thread on which may be fastened 

D. a silver mantel or cover, which can be removed at will, or in 

which holes or windows of any desirable size may be cut, 

such as indicated in E, to permit the escape of all radiations. 

F. is a short silver mantel which is to be used to produce a smooth, 
ending surface by attaching same to C when the long silver 
mantel D is not to be used. 

G. is one of the great variety of handles which may be readily at- 
tached to B. 

There is also furnished a small plug, which has on its 
lower end a screw thread, which will fit readily in B. To 
this plug may be attached thin rubber hose: Catheters, 
Bougies, etc., to answer any purpose. 


permanent this new therapeutic agent will be largely used 
instead of the X-rays ; but the two will supplement each other. 
Certain diseases promise to yield more readily to treatment 
by radium, and other diseases more readily to X-rays. A dis- 
ease that has attacked different parts of the body of a given 
patient may be better treated in certain regions by radium, and 
in others by the X-rays, and it is quite possible that in some 
cases the two remedies used together on the same area, and 
at the same sitting may accomplish better results than either 
alone." 1 

Fig. 59 

This shows an epithelial cancer of the ear, before and after treat- 
ment by radium. The disease remained cured after one year. (Robert 
Abbe in Medical Record, 66, 321, 1904.) 

Truman Abbe 2 remarks, "The radium rays, -no doubt, 
should be classed with the X-rays, the Coley serum, Adamkie- 
wicz serum, and the various caustics. These have given cures 

1. "Some Physical Properties and Medical Uses of Radium Salts ; 
with a Report of Forty-two Cases Treated by Pure Radium Bromide," 
F. H. Williams, Med. News. New York, Feb. 6 (1904). 

2. Washington Med. Ann. 2, 363 (1904). 


in a few cases of inoperable and malignant diseases, but they 
are far too uncertain to be used except when operation is out 
of the question." 

Lyster, of the Middlesex Hospital, uses radium of low 
activity and pitchblende. He applies pitchblende directly to 
the diseased structure for twenty-four hours, binding it on. 
The radium is permitted to excite only the granulations. 

At the Cancer Hospital, London, radium is used in an ap- 
paratus made of ebonite with a quartz shield. To condense 
the radiations the shield is held against the ulcer. 

Maclntyre 1 applied radium by enclosing it in a small cell 
with a mica face. This was surrounded with a small piece of 
India rubber tube which fitted into the apex of a glass cone. 
This localized the action of the radium to the particular part 
to which it was applied. 

According to Robarts 2 the treatment is done through a 
rubber pocket. He remarks : "It has been observed that higher 
activity gives better results than lower activity." 

David MacKenzie' 5 does not claim for radium any special 
value over the X-rays. Phimosis scytitis is increased and ruga 
scytitis varies, being increased within the neighboring walls 
of the vessels. He also reports the curing of rodent ulcer, 
tuberculosis, verucca, cutitis, rodent cancer and the disintegra- 
tion of moles. Fragmentation of the covering of coloring 
matter was observed, as after X-ray treatment. The effect 
ot radium is more rapid than that of the Rontgen rays ; that 
is, a tissue reaction is quicker. He, also, states the method 
of application as used ; that radium was not used in carcinoma ; 
and suggests the possibility of applying thorium in large quan- 
tities to septic ulcers. 

Sichel 4 applied five milligrams of radium bromide forty- 
two times to rodent ulcer with success. 

1. British Medical Journal, June 6, July 25 (1903). 

2. American Journal Surgery and Gynecology. 

3- British Medical Journal, Jan. 22 (1904). 

4- British Medical Journal, Jan. 23 (1904). 


Apolant 1 studied the retrogression of carcinoma on mice 
under the influence of radium rays. The carcinoma cells van- 
ished and there was proliferation of the connective tissue. In 
addition to the destructive action, it appeared to induce spe- 
cific absorption of dying carcinoma cells. He remarked that the 
loss of penetrative power imposed such a limit to the effect of 
the radium treatment, that it has rendered it dubious whether 
as a therapeutic agent, it has much of a future. 

Pozzi and Zimniern* reported an improvement in the case 
of cancer by treatment with radium. They, also, called atten- 
tion to the necessity of determining the extent of the dosage. 

Darier 3 noted the rapid and penetrative analgesic action 
of radium in certain cases of cyclitis and irido cyclitis. Prepara- 
tions of low intensity were often capable of rapidly removing 
pain. In two cases of convulsive neuralgia, which came on 
frequently, the attacks ceased after a few applications of radium 
to the temple for two or three days. Radium effected a cure 
of an acute facial paralysis of recent origin. 

Foveau de Courmelles* found by local application of 
radium chloride that the pain from facial neuralgia or cancer 
could be alleviated. He reports, also, that a plaster of thorium 
oxide may be successfully applied in the shape of a sort of 
varnish and the powder may be wrapped in tin foil and applied 
to the face. The. successful treatment of several severe cases 
of neuralgia were reported. 

Pusey 5 gives an excellent resume of the therapeutic possi- 
bilities of radium. Concerning its effects upon the nervous 
system he ,says, "The symptoms are first depression of the cen- 
tral nervous system followed by flexures of the cerebro-spinal 
system. The explanation of these nervous symptoms lies in the 

i. Deutsche Mediciniche Wochenschrift (1904). 
2,. Medecine Moderne, July 6 (1904). 

3. Lancet, March 5 (1904) ; Paper presented before the French 
Academy of Medicine, Feb. 16 (1904). 

4. Progres Med., May 28 (1904). See also his book on the subject.. 

5. Journ. A. Med. Assoc., July 16 (1904). 


disintegration of the nerve cells produced by the Becquerel 
rays. The Becquerel rays affect at the same time the skin, 
epithelium, connective tissue and blood vessels. The effect on 
the last named appears first." 

Holkin, 1 in a very thorough study of the action of the 
Becquerel rays upon the skin, noted the cellular degeneration 
and dilatation of the vessels in normal as well as in lupus tissue. 
The changes appeared only in the most superficial layers of 

From a comparison of Holkin's work and studies of 
Scholz on X-ray burns in young pigs, it is quite evident that 
the action of the two agree very closely, and may be said to be 
identical, with the single difference of the greater depth of 
action of the X-rays. The cells of neoplasm are as susceptible 
as new cells produced by irritation to the effects of the Bec- 
querel rays, but they are of lower resistance, consequently their 
structure is disintegrated and they degenerate before the irri- 
tant cells are so violently affected. 

Pusey insists that radium "will have a definite, though a 
limited field of usefulness in the treatment of regions situated 
in inaccessible locations, where it is difficult or impossible to 
apply the X-rays, but where radiations from radium can be 
applied readily." He reports its application on carcinoma of 
the uterus, rectum and mouth. He reports no definite effect 
from the use of thorium nitrate and oxide. 

Schamberg 2 directs attention to the decided difference in 
the susceptibility of different individual radiations. 

Bulkley 3 reported in one case of lupus better effects from 
the X-rays than with- radium. He applied it successfully in 
case of epithelioma, beneath the tongue and to the tonsil. Treat- 
ment by surgical means would have been difficult. The disease 
disappeared gradually under the influence of the radium. 

1. Archiv f. Dermatologie und Syphilis, 65 (1903). 

2. Journ. A. Med. Assoc., July 16 (1904). 

3- Journ. A. Med. Assoc., July 16 (1904), p. 180. 


Plimmer 1 made a very searching investigation of seventeen 
cases of carefully diagnosed cancer in the Lister Institute of 
Medicine. Not for any case examined did he secure favorable 
results. "The radium had apparently no effect with regard 
either to cure or relief of pain." Several of the patients having 
died, careful microscopic examinations were made of sections 
of cancerous tissue. In all the cases examined no changes were 
found, either in the cancerous tissue or fibrous cell, and none 
were degenerated. According to him it appears as if the emana- 
. tions from radium can only act upon young and growing cells, 
and the altered cells, especially if surrounded by old tissues, are 
less and less affected. If there is a succession of fibrous tisue, 
the cells are not at all affected. It is not clear that he used 
the most modern containers for the radium. 

The etiology of cancer is not yet understood. It appears 
from the sifted evidence that thus far radium offers little 
hope as a permanent cure for the dreaded disease, especially 
after it has become deep-seated. It is generally accepted 
as a fact, however, that temporary relief from pain and a retard- 
ation of a cancerous growth may result from its application. 
Its portability, easy dosage, remarkably localized action, render 
radium a permanently valuable addition to the therapeutic arse- 
nal, for the technique is simple. 

The procedure of Williams, 2 for guidance of others, is here- 
with given : "When not in use the radio-active preparation 
should be kept in a. thick lead box or envelope. When in use, 
preferably, all sides except that side next to the diseased tissue, 
should likewise be covered with thick lead to protect the oper- 
ator. The compound should not be brought near photographic 
plates, unless it, or the plates, be within lead, as it would injure 

"Method. The method of using the radiations from ra- 
dium is simple. If the strongest action from the radium is 
desired, the metal box containing the salts is placed on the part 
to be treated ; in this case the box should first be covered with a 
thin rubber cot, or other suitable substance, which can be readily 

1. The Lancet, Apr. 16 (1904). 

2. The Medical News, N. Y., Feb. 6 (1904). 


removed so that a new cot may be used for each patient and the 
old one burned up. By this means, the radium capsule does not 
come in direct contact with the part to be treated, but is separ- 
ated from it by this new and clean covering. If a weaker action 
of the radium salts is indicated, the capsule should be placed at a 
greater or less distance, according to the needs of the case, the 
intensity of the rays diminishing as the square of the distance. 

"Exposure. It is important to remember that an over 
exposure of a part may result in a burn, and that this burn may 
not become evident in several days after the exposure has been 
made. Further, that the exposures differ for different diseases, 
even superficial ones. Experience, therefore, is necssary to 
judge not only of the proper length of exposure, but also of its 

"Length and Frequency of Exposures. Exposures must in 
some cases be longer, in others shorter, and the frequency with 
which they are given must vary. In some cases the treatment 
should be pushed ; in others harm, rather than good, would 
result from this procedure. The exposure, then, must be 
adapted to the special case, and further experience is necessary 
to decide the best for all cases, but as a general rule, it may be 
said that when the beta and gamma rays of pure radium bro- 
mide (I have discarded the use of the weaker salts) are used 
together, for the treatment of superficial lesions, and the radium 
capsule is placed on the part to be treated, the length of the 
exposure should be ten minutes to one hour, according to what 
the practitioner desires to accomplish. 

"Exposures should not be made every day. Two or three 
times a week seems to me the safer procedure, as by this method 
an interval is given during which progress can be watched. 

"An exposure of many hours would be necessary if weaker 
forms of radium are used, that is radium of 1000 to 8000 activ- 
ity, before any special results could be obtained, and these 
weaker forms would not be so efficient as compared with the 
pure radium. Pure radium bromide is none too strong for the 
work to be accomplished in certain cases ; in those in which the 
full strength is not necessary, the radium, capsule can be placed 
at any distance desired and the exposure can, also, be short- 

In X-ray treatment dermatologists are agreed that great 
care must be exercised as to idiosyncrasy of the patient, kind 
of tube, vacuum, strength of the current, length of application, 


frequency, etc. (See Chapter VII.) It has been asserted that 
radium compounds of a definite strength may be used to obviate 
many of these unknown factors. Piffard 1 sounds a timely warn- 
ing and most reasonably calls attention to the differences which 
exist between the actual radio-activity of naked radium and effi- 
cient radio-activity of a protected compound. "Radium affects 
the photographic film and also the electroscope and electro- 
meter, but it is by no means certain that the radiations that are 
most active photographically are the ones that most strongly 
ionize the air in the electrical apparatus, and it is still less cer- 
tain as to which is the most efficient in its action on the human 

Fig. 60 

Exact representations of a giant-cell sarcoma of the jaw of rapid 
growth during two months. On the left the sketch is before treatment. 
The teeth of the lad were so loose as to be readily removed by a string. 
On the right may be seen the improvement after six months' treatment. 
The tumor was punctured with a knife and a tube containing radium 
bromide inserted for three hours at each treatment. Ossification set 
in, the teeth became firm. Remnants of the giant-cells were found, how- 
ever, by a pathological examination of the improved portion. The case 
remains cured at one year from beginning treatment. (Robert Abbe, 
Medical Record, 66, 321, 1904.) 

Danycz 2 demonstrated that the effect is more* intense in 
young than adult animals. He applies this fact to explain the 
selective action of the rays on neoplasms, while they traverse 
skin and muscle without appreciable action on them. 

1. Henry G. Piffard, Medical Record, June 18 (1904). 

2. Action du Radium sur les differents tissues, Danycz. Semaine 
Medicale, Paris, 24, No. i (1904). 



Fig. 6 1. -Apparatus of L,ieber for application of radium compounds 
in medicine. The tubes are of aluminum. (Through courtesy of Hugo 

The envelope of thin aluminum, for reasons already noted 
according to Lieber, gives greater efficiency than one of glass, 
mica or quartz. Morton suggests cellulose containers. 

It is assumed, of course, that any physician inaugurating 
experiments on human subjects will have determined the 
strength of the preparation before applying it. Even with that 
knowledge, little is known to-day of the dosage. As adverted 
to, the pathogenic action, i. e. the destructive effect, evidences 
itself in temporary hyperaemia or extensive necrosis accom- 
panying a long enduring ulcer. The difficulty in judging this 
is due to the fact that oftentimes weeks intervene before ulcera- 
tion becomes apparent. Robert Abbe 1 learned that, as a result 
of plunging a tube into a mammary tumor, the inactive encap- 
sulation of radium when put into healthy muscular tissue and 
peritoneum of animals, is no criterion for its action on morbid 
tissue when buried within the tissues. Upon superficial healthy 
tissue, radium compounds bring about necrosis by over excita- 
tion ; upon morbid cells they induce retrograde changes and a 
substitutive fibro-hyperplasia. 

Williams says that under no circumstances should the /?- 
and y rays be used together for deep-seated diseases, because 

i. Loc. cit. 


the /3-rays would cause serious injury before the y-rays had 
time to produce a beneficial effect. 

Einhonn compared the penetrating action of similar prep- 
arations of radium with glass, hard rubber, celluloid, alumi- 
num and ivory. Photographic effects indicated that the first 
three allowed the penetration of the rays better than the last 
two. He, also, suggested the use of radium in the transillu- 
mination of various organs of the body. A capsule of radium 
was held between the tongue and teeth. The cheekbones 
became transilluminated. The suggestion was made that the 
method might perhaps have a diagnostic use in the diseases of 
the antrum. By the use of his "radio-diaphane" the radium 
can be carried into the oesophagus, stomach, or rectum. The 
method of procedure is as follows : 

"The patient is examined with an empty stomach ; growths 
from the thorax and abdomen being removed, the radio-dia- 
phane is slightly moistened and introduced into the stomach. A 
fluoroscope, with barium platino-cyanide screen, is used in. ob- 
serving the rays. All observations must be noted in the dark 
and after the eyes have become accustomed to the darkness. 
The apparatus served satisfactorily in determining the position 
of the large curvature of the stomach ; the descending colon or 
sigmoid flexure, also, may be transilluminated by means of 
radium, if the radio-diaphane, (Fig. 62), in the bowel is shorter 
and of stiffer rubber. The bowels should be thoroughly flushed 
with one or two quarts of water previous to the examination. 
The instrument is introduced as far as possible without kinking, 
the patient being placed on his back. The lower abdominal 
region is inspected by means of a fluorescent screen. It usually 
requires the inspiration of air to become visible ; deep inspiration 
seems to lessen, while low inspiration increases the luminosity."" 
In transilluminating the lungs from the esophagus, he learned 
that it was possible to examine them anteriorly and posteriorly. 

"Normally, moonshine appears where the lungs are ; a faint 
shadow corresponding to the heart, is observed on the left side. 
Doubtless marked inflation of the lungs would cause a change in 
the transilluminancy." 

:. Medical Record, July, 1904, p. 164. 



Fig. 62. The Radiodiaphane. 

By the transillumination of the stomach it appears possible 
to discover tumors, as Einhorn reports he observed in one case. 
He has, also, treated esophageal cancers in this way with 
radium. In one case he was able to enlarge a stricture of the 
esophagus. At first only the smallest size bougie could be 
passed as far as the lower third ; after a month's treatment, 
however, it improved so that a No. 30 bougie was passed into 
the stomach and there was no difficulty in swallowing food. 
From the few cases observed it appeared that partial shrinkage 
of tumor causes the stricture to be reduced. There were no 
disagreeable occurrences incidental to the treatment. There 
was a diminution of pain in some cases, but not in all. No 
complete cure is reported, but decided improvements were 

Exner 1 reported three cases of dilatation of stricture by 
similar treatment with radium. The stricture resulted from 
esophageal cancer. 

As a further illustration of the variety of evidence and its 
frequent contradictory character, attention is directed to the 
statement of Metzenbaum, 2 who says: "From very careful 
observations no difference could be noticed in the physical or 
therapeutic results when using radium of 100 activity or 7000 

1. Wiener klinische Wochenschrift, IV (1904)- 

2. Louisville Journal of Medicine and Surgery, 188 (1904). 


Darier 1 is reported as having used radium successfully as 
an analgesic and as a curative agent in nervous spasms and 

Touching the action of X-rays on bacteria, Bear 2 experi- 
mented with bacillus coli communus, bacillus typhosus, staphy- 
lococcus, streptococcus, Klebs-Loefler bacillus, etc., using an 
exposure of one hour at a distance of ten inches, and found no 
effect, whatever the make of the tube or the method of excite- 

Aschkinass 3 and Caspari 4 first showed that the rays of 
radium interfere with the development of bacteria. PfeifTer 
and Friedberger proved its bactericidal action on saprophytic 
as well as pathogenic microbes. Dixon and Wigham, 5 con- 
tinuing their experiments on the action of radium bromide on 
plants, found in the case of certain bacilli, for example B-pyo- 
cyaneus, typhosus, prodigiosus, and anthracis in an agar culture 
medium, that the /3- radiation exercises a marked inhibitory 
action on their growth. A four-day exposure at a distance of 
4.5 c. m. of 5 m. g. of radium bromide does not appear suffi- 
cient to kill the bacteria, but arrests their growth, and main- 
tains a patch on an agar plate, inoculated with any of these 
organisms, sterile. A broth tube, however, inoculated with 
these in most cases developed the organisms, showing that 
while the growth was inhibited in the patch, all the organisms 
were not killed. 

Henry Crookese has shown that various bacterial cultures 
after exposure to the action of 10 mgms. of radium bromide, 

1. Consular Report, Guenther, Frankfort, Germany, Mch. u (1904). 

2. "Effect of Rontgen rays on Certain Bacteria," Journ. Advanced 
Therapeutics of New York, June (1903). 

3- Arch. f. d. ges. Physiol. (Bonn), 86, 603. 

4. Allg. Med. Centr. Ztg. (Berlin), 72, 590 (1903). 

5. "Action of Radium on Bacteria," Nature. 

6. "Bactericidal Properties of the Emanations of Radium," Chem. 
News, 87, 308. 


about 3 cms. distant, were killed. When the plates were incu- 
bated for 24 to 48 hours, it was noted that the immediate por- 
tion of the plate which had been subjected to the action of the 
rays showed a bare space free from bacterial growth. 

Experiments in our laboratory (University of North Caro- 
lina) by Manning, with radium chloride of 7000 activity, indi- 
cated an actual stimulation of their growth. 

Green 1 found that when bacterial cultures were subjected 
to the action of radium bromide and then removed, they pos- 
sessed sufficient activity to affect the photographic plate, even 
through a double layer of lead foil. 

Van Buren and Zinsser 2 report the result of the effect of 
radium of 300,000 activity upon bacteria. They exposed the 
bacillus typhus, staphylohemia, pyrogensis aureus from 8 to 19 
hours in the dark without any effect. They say this may have 
been due to the fact that the radium' was confined within glass 
or on account of the shortness of exposure, but they assert that 
their observations give small promise of achieving brilliant 
therapeutic results with it as a bactericide, as prophesied by 

Prescott 3 arrived at the following conclusions : 

Radium rays have no effect upon fresh cultures of B-coli, 
B-diphtheriae, or saccharomyces cerevisiae at a distance of one 
centimeter when the time of exposure is less than ninety min- 

Any advantages derived from the therapeutic use of 
radium must be explained in some other way than by the direct 
weakening or destruction of the micro-organisms of disease. 

The use of radium tubes in the treatment of diphtheria 
cannot be recommended or regarded as a substitute for anti- 

Ackroyd 4 studied the action of radium on milk, and 
Schmidt-Nielson reported that the action of radium in the 

1. Nature 70, 69. 

2. American Medicine, Dec. 26, 1903. 

3. Science, N. S., 20, 247. 

4. Nature 70, 55 (1904). 


curdling of milk is minimal. Any action it showed upon the 
chymosin was attributed not to the Becquerel rays, but to the 
phosphorescence of the generated ultra-violet rays. 

Dr. Margaret Mary Sharpe, of London, appears to have 
been the first to use radiant matter in the removal of hair as a 
professional procedure. 

From what we have learned there appears to be little in 
the suggestion that radio-activity may supplant chemicals used 
for the preservation of food. 


>' v<r 

Fig. 63 

This shows the hindering effect a radium compound has upon the 
germination of seed. (Through the courtesy of Dr. Robert Abbe.) 

It has even been suggested that radium will solve the prob- 
lem .of determining the sex of children before birth. 

Many other suggestions have resulted from the unchecked 
play of imagination ; for example, the prevention of mal de mzr 
by the use of radium. 

Soddy is reported as having suggested the inhalation of 
thorium emanations for tuberculosis. Tracy, by a photographic 
method, reports the radio-activity of the breath after such 

Soddy has noted that if a radium salt be dissolved in 
water the emanations are immediately evolved, and collect in 



the air above the solution. If the emanations be swept at once 
into the lungs they serve as a germicidal agent in tuberculosis. 
Lieber asserts its value in the case of hoarseness with himself. 

Morton states he saturated distilled water with radium 
emanations and this was administered to the patient. It 
appeared to create fluorescence in the medicines that may have 
been previously administered. Apparently the rays thrown off 
from the fluorescing substance become healing agents. This 
mode of treatment has also been used by Paul-Edward, Radio- 
grapher of the General Hospital, London. 

Blood has been removed from persons who have acquired 
radio-activity. It affects photographic plates through translu- 
cent substances. This is a case, apparently, of induced activity. 

The method, according to Morton, of saturating the water 
is shown in the accompanying figure. (Fig. 63.) 

Fig. 63 

Morton's method for saturating water with the emanations of 
radium. The radium compound is in the open vessel in flask 2. Gas 
is forced by the compressor, 3, over the radium, to sweep the emana- 
tions through the water in i. 

Saake 1 refers to the radio-active substances of the air 
reported by Elster and Geitel as being from 3 to 5 times as 
great in the mountains as at the level of the sea. ''The differ- 
ence in the tension between the positive air and the negative 

i. "Ein. bisher unbekannter Faktor des Hohenklimas," Munchener 
Med. Wochenschrift 51, i (1904). 


earth the potential also increases with the altitude. Experi- 
ments indicate that these electric and radio-active factors have 
some share in the benefits of the mountain climate and they 
might be artificially increased." The writer repeats such state- 
ments with trepidation, for all have been either misunderstood 
or unwarranted conclusions drawn by the zealous newsgather- 
ers with unfortunate consequent delusions on the part of the 
ill. One instance is reported 1 where at least "one shrewd specu- 
lator in human misery proposes soon to start a sort of radium 
consumption farm, where he will advertise to do wonders for 
affected lungs by means of radio-active air and handsome 

Frequent suggestions have been made to prepare salves, 
ointments, etc., with chemically inert preparations of radio- 
active substances. 

Morton 2 has inaugurated a novel method of treatment by 
which the introduction of light within the human tissues them- 
selves is claimed. The X-ray and radium compounds are used 
merely as exciters of the fluorescent substances already within 
fluids of the human body or by injected fluorescing substances. 
He says, 3 "I now regard the X-ray and radium as exciters of 
light, and I think that the curative effects are due to the fluores- 
cent qualities of the fluids of the human body, particularly when 
these fluids have -been made more fluorescent, that is to say, 
artificially fluorescent by the use of various fluorescent solu- 

Metzenbaum, however, says: "The conclusions drawn 
from nearly one hundred experiments give positive proof that 
while suspending tubes of radium of various strength for long 
periods in various solutions and various powders, that neither 
these solutions nor the powders are capable of affecting photo- 
graphic plates, and are therefore not rendered radio-active, and 

I. "The Sense and Nonsense about Radium," Cleveland Moffett, 
Success, April (1904). 

2.. New York Medical Journal, Feb. 13 and 20 (1904). 
3. Personal letter to the writer. 


therefore neither the solution nor the powders can in any way 
affect the metabolism or pathology of living organisms." 

In view of the most recent work of Ramsay (Chapter V), 
it does not seem improbable that substances may become radio- 
active without actual contact with the emanations. 

It is too soon to draw any conclusions from much that has 
been done. It is unwise to make any final statements. How- 
ever, we know this much : that the radium rays possess the 
power of dilating the vessels ; that they have an electric action ; 
also, an influence upon the cells of quickly growing tissues and 
possibly bactericidal properties. These three factors give bright 
promise of its therapeutic use, when we shall have learned more 
about this wonderful substance. 



The Rontgen Rays. 

Attention has already been directed to the fact that when 
a Crookes tube is placed in series with the poles of a static 
machine, or the secondary terminals of an induction coil, it 
becomes the seat of three classes of radiations: (a) the anode 
rays, or kanalstrahlen of Goldstein; (b) the cathode rays; 
and (c) the X-rays of Rontgen. 

The Goldstein rays are confined to the interior of the 
tube and hence, from the standpoint of the physician, are neg- 
ligible. The cathode rays are much more penetrating and in 
part, according to Oliver Lodge, 1 traverse the tube and possibly 
may be the chief factor in producing the cutaneous reaction 
that is observed when the Crookes tube is employed for thera- 
peutic purposes. The X-rays are without the tubes. These 
are vastly more penetrating than the others. This penetrating 
power varies inversely with the density of the substance on 
which they impinge. Substances opaque to light, as aluminum, 
are readily penetrated, while many substances transparent to 
light, as rock salt, are remarkably opaque to the X-rays. 

It was known for some time that the Rontgen rays, in 
addition to their value as an aid to surgical diagnosis, possessed 
peculiar properties which gave promise in the treatment of 
certain forms of disease, especially those affecting the skin. 2 

1. Archives of the Rontgen Rays, April (1904). 

2. "Lupus," Pusey, Journ. Am. Med. Ass'n., 35, 1476 (1900). The 
method of Schiff and Freund, of Vienna, was used. In calling atten- 
tion to the work of Kummel, Pusey states that certainly none of the 
usual methods of treatment by surgical means could produce such a 



For a clearer conception of this phase of our subject it 
becomes necessary to call attention, incidentally, to some of the 
most recent work in the application of the "X-light" to the 
treatment of disease. The reader interested in such may secure 
first hand knowledge of this form of medical practice by refer- 
ring to fuller and authoritative works. 1 

The illustration shows a case before and after treatment with X- 
rays. A. D.. twelve years of age. Microscopical diagnosis, lympho- 
sarcoma after first operation and round-celled sarcoma after second 
operation. Duration, seven years. (Williams, Medical News, Feb. 6, 

Pusey 2 reports the favorable treatment of sarcoma by 
X-rays, and says that in certain cases, which cannot for any 
reason be treated successfully by surgical means, the effect of 
X-rays should be tried. And further, that in cases of sarcoma 

i. As for example, F. H. Williams's, "The Technique of X-ray 
Therapy as Applied to Diseases of the Skin," and L. E. Schmidt, Journ. 
Am. Med. Assn., 40, n, 1903. Also Rollins. 

2.. Journ. Am. Med. Assn., 38, 166. 


which have been treated surgically, the subsequent use of 
X-ray exposures as a prophylactic, is a procedure which should 
be considered. 

Bartholmy 1 reports a number of cases of cutaneous lesions 
produced by the application of the X-rays. He urges caution, 
and states that it is still premature to introduce the radio- 
therapy in a current practice, one case of burn being observed 
five minutes after the first application. The physician should 
not be held responsible for this, any more than for death during 
chloroform narcosis, when all the rules of science have been 
complied with. In spite of precautions, accidents are liable 
to happen when least anticipated. 

Rurio-Jicinsky 2 lays down general rules for treatment with 
X-rays, concerning the kind of tube to be used in protection of 
the hair, eyes, etc., while Ross and Wilbert 3 found the anaes- 
thetic effect of the X-ray a decided advantage, though they 
did not find it was valuable as a curative agent in all malig- 
nant growths. 

Leonard 4 in writing of the Rontgen treatment of malig- 
nant diseases, states that the alterative and destructive action 
produce retrograde changes. In large subcutaneous growths 
of low vitality, such a rapid destruction may take place as to 
flood the system with toxins and cause a fatal auto-intoxica- 
tion and septicemia." The bad effects noted by some observers, 
such as the stimulation of the growth of tumors, were probably 
due to this cause, or to under stimulation by too small a dosage. 
Operative treatment should precede and the X-ray treatment 
deal with the residue that has escaped the knife. "It must be 
employed with as great care as any other agent possessing 
such marked alterative properties." 

i. Annales de Dermatologie, Paris, February, 1901. 

2.. N. Y. Med. Journ.. Nov. 15, 1902. 

3. Therapeutic Gazette, Detroit, Feb. 15, 1903. 

4. Phila. Med. Journ., Feb. 14 (1903). 


Walker i reports the cure of a case of alveolar melanotic 

Coley, 2 summarizing the X-ray treatment of malignant 
tumors, states that they have an inhibitory action on all forms 
of malignant tumors ; yet the number of cases is insufficient 
to enable us to state what particular varieties are most suscep- 
tible to these influences. 

Pfahler;' in his comments on X-ray treatment of cancer 
says : "To-day the medical profession seems to recognize it 
as a valuable therapeutic agent in certain forms of cancer.'* 
Among other conclusions drawn, he states that the time re- 
quired to cure superficial cancer is usually from two to six: 
months. "We can recommend the use of X-ray in all carci- 
nomata, but especially in those that are inoperable or in which 
operation is refused." 

Again this same author* gives a number o J f conclusions 
drawn from treatment of carcinoma and tuberculosis with 
Rontgen rays. Among these it may be mentioned that the 
X-rays are of undoubted value in the treatment of certain 
cases of both superficial and deep-seated carcinoma and tuber- 
culosis. Yet there are idiosyncrasies in certain persons which: 
render them most susceptible to the X-rays. In these people 
deeper burns may occur, in spite of the most careful treatment. 
Epithelioma involving the mucous membrane is much less likely 
to be involved in these effects than that which involves the 
skin. There is not likely to be any interference with the sense 
of sight, even if the X-rays are used directly over the eye. 
Tuberculosis, whether 'of the skin or of the glands, yields in 
certain cases to the X-rays. Epithelioma of the mucous mem- 
brane should be removed as soon as possible by the knife and 
that followed by the X-ray treatment. Operable cases should 
be operated on and that followed by the X-ray treatment. 

1. Journ. Am. Med. Assn., 40, 1214 (1903). 

2. Med. Record, New York, March 21 (1903). 

3. Journ. Am. Med. Assn., 40. 8. 

4- Journ. Am. Med. Assn., 41, 1406 (1903). 


The X-ray is "not only a very valuable therapeutic agent 
but also a very dangerous one," for as Zeisler 1 has said, ''Who- 
ever is making extensive use of the Rontgen rays is bound to 
have, sooner or later, some unpleasant experience with the much 
dreaded X-ray burns." 

The following diseases have been treated by the X-rays 
with variable success : 

Lupus vulgaris and erythematosus, scrofuloderma, hyper- 
trichosis, acne, sycosis, epithelioma, psoriasis (not permanent), 
lichenplanus, keratosis palmaris, eczema and pruritus, clavus, 
hyperidrosis nasi, and dermatitis staphylogenes. 

Concerning X-rays and cancer, the editor of the Journal 
of the American Medical Association says, "That the X-rays 
have a powerful effect on tissue is undeniable. The evidence 
seems strong, if not altogether conclusive, that they have a 
selective action on certain morbid celled proliferations; that 
they check malignant growth by their destructive action on 
the surrounding healthy tissues is so much less that it can be 
safely considered as negligible when the beneficial effects are 
taken into account." 

Ultra-Violet Rays. 

The spectrum of the solar rays, as we analyze them at the 
earth's surface, is found to consist of three distinct portions: 

(1) At the lower- end certain invisible radiations of compara- 
tively long wave-length, and commonly spoken of as the infra- 
red portion of the spectrum. So far as we are aware there 
has been no separate and distinct therapeutic application of 
these rays, other than their employment as thermic agents. 

(2) The luminous portion of the spectrum with its colored 
gamut from red to violet, passing upward from B longer to 
shorter wave lengths from Fraunhofer's lines A to H. (3) 
The invisible portion of still shorter wave-lengths and indef- 
inite extent, known as the ultra-violet. 

Near the surface of the sun this region is undoubtedly 
of very great length, but as the undulations pass through the 

i. Journ. Am. Med. Assn., 40, 511 (1903). 


atmosphere, the waves of shortest length are absorbed and 
do not reach us. Fortunately these shorter undulations become 
known to us through artificial sources and it is by this means 
that physicians have been enabled to utilize the ultra-violet 
rays in the treatment of disease. 

The chief sources of the ultra-violet rays, available for 
experimental purposes, are the electric arc and the radiations of 
the spark of the high tension current of a transformer in con- 
nection with a condenser. 

The electric arc with carbon terminals emits a larger rela- 
tive proportion of ultra-violet rays than we find in the solar- 
radiations. If iron terminals be substituted for the carbon, 
the proportion of ultra-violet is still greater; and if the con- 
denser spark is made to pass between iron terminals, we will 
have the richest source of ultra-violet rays now known to us. 

The most convenient means for detecting the ultra-violet 
rays are their effect on certain fluorescent minerals, notably 
willemite and calcite and their ability to ionize gases, as 
shown by their effect on a negatively charged electroscope. 

Willemite associated with calcite and other minerals from 
Franklin, N. J., and calcite associated with schefferite and 
braunite from Sweden, serve admirably as aids to an approx- 
imate valuation of the ultra-violet rays, as shown by Kunz and 
the writer. 

When subjected to the rays from the carbon-arc willemite 
fluoresces green, but the calcite is unchanged; to the iron-arc 
the green fluorescence is more brilliant and the calcite changes 
from white to very faint pink ; when exposed to the rays from 
the condenser-spark, between iron terminals, the green fluor- 
escence of the willemite is extremely brilliant, the calcite is 
changed to a bright pink, and in specimens from Sweden to 
a brilliant red. 

When an electroscope, charged negatively, is exposed to 
the carbon-arc (Finsen-Reyn lamp) it is slowly discharged; 
that is, in from five to ten minutes ; when exposed, at the same 


distance, to the iron-arc, in from one and a half to two min- 
utes; and when exposed to the condenser-spark, between iron 
terminals, in less than half a minute. The discharge of the 
electroscope in these instances is brought about by the ioniz- 
ing influence of the ultra-violet rays on the air that lies be- 
tween the parallel plates of the electroscope. The ionized air 
thus becomes a conductor of electricity and this permits the 
charge of the insulated gold-leaf to escape to earth. 

The therapeutic utilization of the luminous as well as the 
non-luminous portions of the spectrum have been thoroughly 
and well discussed by others, especially on account of the bril- 
liant work of the lamented Finsen. 

The Piffard-Rays. 

Recently there appeared a paper 1 describing what may be 
termed the Piffard-rays, after the physician who discovered 
them and who is using them with success in his practice. 

The lamp (Fig. 65) is furnished in front with a thin 
quartz plate, which is transparent to ultra-violet rays, while 
glass is opaque to them. If the face of the lamp, with the 
quartz in situ, be applied to a piece of photographic paper 
(Solio) and the lamp actuated by a suitable coil, a strong im- 
pression will be made on the paper in about thirty seconds. 
If the experiment is repeated with the quartz removed, the 
result is substantially the same. 

Ultra-violet rays, as is well known, will discharge an 
electroscope if charged negatively but not if charged posi- 

On trial Piffard found that the lamp with the quartz in 
front discharged the negative electroscope in about 20 sec- 
onds, but with the quartz removed discharged it instantly ; that 
is, within less than one second. He also found further that 
the radiations from the unobstructed spark would discharge 
an electroscope charged positively. 

It was clear from this that in addition to the ultra-violet 
rays he was dealing with another class of radiations that only 

i. The Medical News, 85, 1057 (1904). 


Fig. 65. Piffard's Ultra- Violet Lamp. The technique recommended 
is as follows : If the appliance be used with a ceil, a single Leyden jar 
should be employed, with inner armature connected with one of the 
secondary terminals, and the outer armature with the other terminal of 
the secondary of the coil. The lamp is then connected directly to the 
secondary by its cords. Piffard prefers a Wehnelt interrupter adjusted to 
give a current of five to six amperes through the primary of the coil. 
The armatures should not exceed 40 square inches of foil in each. This 
is for the three spark lamp. For the one spark "ionizer" a lesser amount 
of energy is preferable. The first application should never exceed ten 
minutes. If connected with a static machine use two Leyden jars, 
the armatures cf which should each have a foil surface of at least 100 
square inches. The outer armatures of the jars should be connected 
together, and the lamp terminals connected to the pole pieces of the 
static machine. The first application should not exceed 15 minutes 
with the spark from 15 to 20 millimeters from the lesion. 

slightly affected the photographic plate, but acted very ener- 
getically on the electroscope. 

In default of any means of determining the exact nature 
of these radiations he assumed that they were negative elec- 
trons and predicted that they would act very energetically on 
the skin or any other tissue with which they came in contact; 
that the character of the reaction would resemble that from the 
X-rays and radium, except that it would make its appearance 
more promptly. 

If the radiations in question were negative electrons, as 
apparently are the cathode rays of the Crookes tube, and the 
beta rays of radium, they would of course be deflected by a 
strong magnetic field, which Pegram and Milton Franklin 
found was not the case. 



V%---^.- ( Jh WAITE &IBARTLETT M.F.G' CO. N.Y. ( 9i) 

Fig. 66. Piffard's Electroscope, later model. 

E. Wiedemann 1 described a new form of radiation to 
which he gave the name of Entladungsstrahlcn, and stated 
that it was not deflectible by the magnet and would not pass 
through fluorspar which readily transmits the ultra-violet rays. 
He does not appear to have examined the radiations with the 
electroscope. It is quite possible therefore that Wiedemamrs 
observations related to the Piffard rays. 

In discussing the question of ions, J. J. Thomson says/ 
that if we have a spark one centimeter long in connection with a 
condenser of 1000 c. m. capacity the pressure developed will 
be equal to that of 660 atmospheres, (equal to about five tons 
to the square inch). This pressure, however, diminishes with 
the distance from the spark according to the law of inverse 

When we consider the enormous velocity with which ions 
are projected in consequence of the pressure behind them, and 

1. Zeitschrift fur Electrochemie, July 20, 1895. 

2. Conduction of Electricity through Gases. Cambridge, Eng., 1903, 
p. 392. 


the rapidity with which they are developed, it is quite within 
reason to assume that they will be capable of exerting a con- 
siderable influence on tissues that are brought within a centi- 
meter or two of their point of origin. Piffard has found, 
clinically, that his rays do exert a very powerful influence on 
the skin; and that the reaction is similar in character to that 
of the X-rays and of radium ; and that it appears much more 
promptly. Like them also it may produce a curative or a 

Fig. 67. Piffard's Spark-ionizer. 


destructive effect according to the intensity of the spark and 
the duration of its application. 

When the spark is produced between iron electrodes, with 
one or more intervening gaps, the total length of the gaps 
need not exceed one centimeter. If the lamp be used in con- 
nection with a coil and suitable condenser, an application of 
about five minutes with the sparks about 15 m. m. from the 
tissue, a decided reaction will be obtained in soft morbid 
epithelial and other degenerating tissue. A similar applica- 
tion for 15 minutes has resulted in the sloughing out of a lupus 
nodule. It is important, therefore, that care should be used 
and especially at the beginning of treatment in any given case. 
These condenser spark radiations have also been used suc- 
cessfully by Robert Abbe, Milton Franklin, and Dieffenbach. 

The use of X-rays in connection with uterine cancer and 
some epitheliomatous conditions of the buccal cavity present 
mechanical difficulties that it is sometimes inconvenient to 
overcome. Piffard, to overcome such in the application of 
his rays, designed what he calls a "spark-ionizer," which may 
be introduced through a speculum or other suitable shield. 
The name is given on account of utilization of both the ultra- 
violet light and the ions ( ?). 

While it is too new for unqualified statements the indica- 
tions certainly are promising. 



Abbe 116, 122, 126, 133, 152 

Absorption, power of different 

rays (Beequerel) 16 

Ackroyd 44, 137 

Acne 12f 

Actinium 5 

Actinium At. Wt 58 

Actinium emanation 1)1 

Actinium from pitchblende 56 

Actinium methods of separation 56 
Actinium oxide and radium bro- 
mide - r >7 

Action of radio-active Th 49 

Action radium bromide and ac- 
tinium oxide 57 

Adamkiewicz serum 126 

Adams 65 

Aeschynite 20 

Af anas jew 21 

Alexander 108 

Allan 65 

a and/2 bromo-allo-cinnamic acids. 44 
a and j3 particles comparison. .114 

a and ft particles Laws of 110 

a emanations order of penetra- 
tion 41 

a rays, properties of 15, 40 

Alveolar melanotic sarcoma 145 

Aluminum tube for radium (Lie- 

ber) 125 

Amber photographic action of 

Beequerel rays through 13 

Anode 1 

Anode rays 142 

Antitoxin 137 

Autunite 13, 20, 21 

Apolant -. 127 

Apparatus for applying radium 

compounds 123 

Apparatus for application radium 

compounds 133 

Apparatus for condensing the 
emanations . . . 80 

Apparatus for examination active 

body Curie 17 

Apparatus for illustrating the dif- 
fusions and condensation of 

emanations 71 

Apparatus for demonstrating em- 
anation of radium is a gas 70 

Apparatus for determination of 

electrical conductivity 35 

Apparatus of Dewar and Curie. . . 31 
Apparatus for showing ratio of ra- 
dium and uranium 99 

Apparatus used by Mine. Curie 
for measuring the intensity of 

radiation 18 

Application of radium preparation 
in local treatment Morton. .. .122 

Armstrong and Lowry 103 

Arnold 9 

Arsonval 9 

Aschkinass 136 

Atomic Degradation 103 

At. Wt. constituent Ceylon Min- 
eral 53 

Atoms electrically charged 97 

Austrian Government 24 


Bacilli 136, 137 

Bacterial Cultures 136 

Bacterial growth 137 

Barium similarity of radium to. . 28 

Barium artificial active 64 

Barium Bromide, radio-activity of 27 
Barium platino-cyanide screen... 6 
Barium Sulphate emanation X .. 87 

Barker 50 

Barnes Heat emission, etc., ra- 
dium emanation 81, 89 

Bartholmy 144 

Baskerville 9 

Baskerville Inactive thorium. . .107 
Baskerville Radio-active thorium 

from monazite 52 

Baskerville Thorium constituents 98 



Baskerville and Kunz Tiffnnyite 

diamond 84 

Baskerville and Kunz Thuringian 

glass, etc 74 

Baskerville and Lemly separa- 
tion thorium, etc 51 

Baskerville and Lichteuthaeler. . . 63 
Baskerville and Lockhart Effect 
on diamonds from condensed 

emanations 74 

Baskerville and Lockhart rare- 
earth minerals 77 

Baskerville and Lockhart theory 

of 101 

Baskerville and Zerhan Thorium 

from South American Mineral.. 52 
Baskerville and Zerban Th. from 

South American Mineral 99 

Batelli and Maccarone 90 

Bear 136 

Beattie 11 

Becquerel activity uranium not 

constant 94 

Becquerel a particles 40 

Becquerel-a rays 15 

Becquerel black light 9 

Becquerel Conversion yellow P. 

to red 43 

Becquerel energy from uranium. 16 
Becquerel examination of polo- 
nium 54 

Becquerel X-Rays 41 

Becquerel invisible radiations of 

uranium 46 

Becquerel radium sore 115 

Becquerel secondary radio-activ- 
ity of metals 85 

Becquerel speed corpuscles from 

radio-active substances 106 

Becquerel uranium 47 

Becquerel Rays 13. 18 

Becquerel rays effect on nerve 

cells 129 

Becquerel and Curie .116 

Beilly 83 

Bemont 22 

Benoist 42 

Berndt 53 

Berthelot 36, 44 

ft Rays properties of 14 

ft or Cathode rays 38 

Bismuth, platinum and palladium 55 
Bismuth property of emitting 

rays 55 

Bismuth and radio-tellurium.. .. 61 

Black 19, 43 

"Black Light" 9 

Blandamur 119 

Blende, Sidot's 9 

Blood 139 

Bohemian pitchblende 48 

Bohm 120 

Boltwood apparatus for showing 
riatio of radium and uranium.. 99 

Boltwood 23, 24, 25, 103 

Borgman 66 

Bougie 135 

Broggerite 13 

Broggerite, extraction two ele- 
ments ( ?) from 59 

Broggerite two elements from 

and at. wts 59 

Brooks 79, 87 

Buckwalter 14, 15 

Bulkley 129 

Bumstead and Wheeler 65 

Bun sen Colorimeter 31 

Burton . ..65, 67 

Calcite and Willemite 147 

Calcium sulphide, phosphorescent 9 
Cameo, photographic of Becquerel 

rays through 13 

Cancer 127, 145, 146, 152 

Cancer, epithelial 126 

Cancer etiology 130 

Cancerous tissue 130 

Carcinoma 128 

Carcinoma of the oesophagus. .. .121 

Carnotite 14, 20 

Carnotite extraction of radium 

from 25 

Carnotite impression 14 

Carolinium 53 

Caspar! 136 

Catalytic agent 97 

Catalysis radio-activity a form of 97 

Cathode % 1 

Cathode rays 2, 6, 142 

Celluloid, etc. loss of activity . . 91 

Cervix uteri 124 

Cerebo-Spinal flexures 128 

Ceylon Mineral 52 

Chalcolite 20 

Chalcolite artificial, radio-activity 

of 21 

Chemical action radium com- 
pounds 43 

Chymosia 138 


Clark Cell 44 

Cleaves 123 

Cleveite 13, 20 

Clock Strutt's Radium 10.~> 

Coley 145 

Coley serum 120 

Coli communus bacillus 136 

Collier 13 

Condensation of radium emana- 
tion 81 

Corneal Opacity 118 

Conductivity of the Air 34 

Cook 66 

Coppel 35 

Coral, luminescence of under the 

action of cathode rays 3 

Cornwallis 20 

Corpuscles 4, 5 

Crookes, Henry bacterial cul- 
tures 136 

Crookes and Dewar 73, 88 

Crookes and Thomson 101 

Crookes a rays 40 

Crookes deviable rays and ca- 
thode 94 

Crookes Elster and Geitel 55 

Crookes examination uranium 

minerals, etc 11 

Crookes Investigation of phe 

nomena in high vacua 2 

Crookes photographic method ... 52 

Crookes polonium 53 

Crookes radiant mater of radium 70 
Crookes radio-active elements 
and abstraction energy from a 

gas 100 

Crookes's Railway Tube 4 

Crookes's Rays 103 

Crookes's Spinthariscope 73 

Crookes study spark spectrum, 

radium 28 

Crookes Tube 2, 7, 142 

Crookes tube provided with a 

window 3 

Crookes uranium 36 

Crookes uranium nitrate 47, 48 

Cryellitzer 117 

Curie and Debierne 73, 77, 90 

Curie and Danne 76, 70 

Curie and Dewar 83 

Curie and Giesel 30 

Curie, Mme. S. a- rays polo- 
nium 40 

Curie and Laborde 30, 31, 06. 100 

Curie and Rutherford.. ...93 

Curie, Mnie. S. apparatus for 
measuring intensity of radiation 18 

Curie, Mme. S. artificial chalco- 
hite 25 

Curie, Mme. S. at. wt. radium... 29 

Curie, Mme. S. bismuth and po- 
lonium 55 

Curie, Mine. S. calcium sulphide 

Curie, Mme. S. estimate of radi- 
um emission 106 

Curie, Mme. S. exam, uranium 
salts 16 

Curie, Mme. S. excited radio- 
activity 85 

Curie, Mme. S. exposure of sub- 
stances to radium 87 

Curie and Becquerel exposure of 
arm to radium 115 

Curie, Mme. S. general theory 
radio-activity 100 

Curie, Mme. S. Law for dissipa- 
tion of excited radio-activity... 01 

Curie, Mme. S. Polonium 53, 54 

Curie, Mme. S. Polonium of 60 

Curie, Mme. S. Preparation of 
artificial chalcolite 21 

Curie, Mme. S. "radio-activity" 
of uranium and compounds 10 

Curie, Mine. S. radio-activity of 
uranium 51 

Curie, Mine. S. radium and Roent- 
gen rays 107 

Curie, Mme. S. Radio-activity an 
atomic phenomenon 04 

Curie, Mine. S. Radio-activity 
uranium, thorium, radium, ac- 
tinium 55 

Curie, Mme. S. radium emana- 
tions 33 

Curie, Mme. S. Radium, power 
of absorbing rays (?) 107 

Curie, Mme. S. Table intensity 
of current with metallic ura- 
nium 20 

Curie, Mme. S. Thorium, radio- 
activity of 48 

Curie, Mme. S. Uranium, thor- 
ium, radium and actinium ac- 
tivity 55 

Curie, P. character of radium 
rays 38 

Curie, P. conductivity of air un- 
der influence of radium 34 

Curie. P. excited radio-activity. 85 



Curie, P. exposure of substances 
to radium 87 

Curie, P. General theory radio- 
activity 100 

Curie, P. Preparation of radium. 27 

Curie, P. Radio-activity uranium, 
thorium, radium, actinium 55 

Curie, P. radium emanations. ... 33 

Curie, P. Radium, power of ab- 
sorbing R. Rays (?) 107 

Curie, P. rate of decay of activ- 
ity, radium bromide 71, 72 

Curie, P. Theory of radio-activ- 
ity 100 

Current of saturation, limiting 
current 18 

Cyclitis and irido 128 

Danlos and lupus patient 119 

Danne, M. Jacques Extraction of 
radium from pitchblende and 

carnotite 26 

Danne 76 

Danne Emanation radium 79 

Danycz 119, 132 

Dauycz and Bohm 120 

Darier 128, 136 

Darwin 106 

Davis 92, 103 

D'Arsonval 9 

Debierne, activity actinium 58 

Debierne Artificial active barium 64 

Debierue excited activity 77 

Debierne excited radio-activity.. 90 
Debierne Factory process; new 
element assximption, radium... 25 

Debierne gas in vacuum 73 

Debierne Radium in vacuum.... 71 

Debierne 90, 91 

Decay of activity 10!) 

De Hemptinne 98 

Demarcay 53 

Demarcay, radium examination.. I'-") 

Demarcay, radium spectrum 28 

Descoundres a rays of polonium. 41 

Descoundres 40 

Desconndres helium spectrum ... 84 

DeSmolan 11 

Detection of radio-activity (Bolt- 
wood) 24 

Dewar nitrogen 83 

Dewar scintillations 73 

Diamonds, luminescence of, under 
the action of cathode rays 3 


Diamond, photographic action of 

Becquerel rays through 13 

Dieff enbach I 52 

Diphtheria 13> 7 

Diseases deep seated 133 

Disintegration of radium atom. 


Dorn 7() 

Dorn and Forch $' 

Du Pont ' ' 

Dutch Metal 41 


Effect of radium bromide on 
photo plate 

Einhorn 1:i4 

Electric charge of cathode rays. . > 

Electric discharge 

Electric discharge in vacuo 

Electrical conductivity 35 

Electric field, action of, upon 

cathode rays 

Electric spark 

Electrometer 1~ 

"Electronides" 102 

Electrons H 2 

Electroscope 7, 8, 9, 41 

Electroscope, action of X rays 

upon the ' 

Electroscope. Mine. Curie's. .. .17, 19 

Electroscope, Rutherford's 2i 

Electroscope, Piffard's 150 

Elements No. of Radio-active 64 

Elster and Geitel, 

11, 16, 38, 66, 68. 139 

Emanation absorption of 76 

Emanation at. wt. 200 81 

Emanation amt. stored in non- 
emanating radium 76 

Emanation changes in 114 

Emanation chemical nature 78 

Emanation condensation of 79 

Emanation decay activity 109 

Emanation heating effect of 89 

Emanation influence radium on 

bodies 78 

Emanation luminosity of 79 

Emanation power of producing 

persists in the atom 

Emanation radiation of 81 

Emanation of radium gas 70 

Emanation rate of decay of 75 

Emanation Thorium vs. radium. 81 


Emanation wt. of HI 

Emanation X 86 

Emanation X. of thorium 87 

Emaniiun 62 

Energy, produce,! by cathode rays 4 

Energy of Becquerel rays 16 

Entladuugstrahleu 150 

Epidermis 115 

Epithelial cancer treatment of. .126 
Epithelioma mucous membrane. .145 

E-rays 90 

Epithelioma 120, 129 

Excited activity 95 

Excited radio-activity 85 

Exposure length and frequency. .131 

Exner 28, 121, 135 

Exner Polonium 53 

Eye . ..116, 117 

Facial paralysis 128 | 

Fehrle 90 

Fergusonite 20 

Finsen-Reyn lamp 147 

Foveau de Courmelles 128 

Fluorescence of glass 10 

Fluorescence of glass in Crookes 

tube 2 

Fluorescing substances 10 

Flourspar, photographic action of 

Becquerel rays through 13 

Forch 92 

Franklin 5, 104, 149, 152 

Friedberger . .136 

Gadaud ......................... 119 

y rays .......................... 41 

Gassiott ........................ 1 

Gates .......................... 86 

Gteissler tube ............. 1, 2, 3, 84 

Gegner prize .................... 22 

Giant-cell sarcoma (Abbe) ....... 132 

Glaucoma ...................... 118 

Globulin, coagulation of ........ 45 

Goldberg ........................ 123 

Goldstein ................... 5, 36, 63 

Green ........................... 137 

Guinea pigs and rabbits ......... 119 

Gummite ....................... 12 

Gutton .......................... 98 

Geitel conductivity in the air, 
etc ......................... 38, 68 

Geitel emanation from the air.. 66 
Geitel radio-active emanation 

from the air, soil, etc 66 

Geitel radio-active substances of 
the air in the mountains and 

level sea 139 

Geitel star effects from soil em- 
anations, on Sidot's screen 72 

Geitel sulphides 55 

Geitel uranium 16 

Geitel uranium rays 11 

Giesel emanating substances and 

E Kays 90 

Giesel's Emanium 62, 63 

Giesel exposure of arm to ra- 
dium 115 

Giesel Penetrating power of po- 
lonium radiation 53 

Giesel Polonium of 61 

Giesel radio-active lead 60 

Giesel radio-activity of thorium 50 
Giesel radiations from an excited 

piatinum wire 87 

Giesel action radium on plant 

growth 116 

Giesel (3 or Cathode rays 38 

Giesel Bismuth and polonium so- 
lution 55 

Giesel Temperature of impure ra- 
dium salt 31 

Giesel and Crookes uranium 94 

Giesel water solution of radium 
salts 28 


Haitinger 99 

Halzkuecht and Schwarz 117 

Hallopean and Gadaud 119 

Hammer 33 

Hardy 45 

Haschek 28 

Heat disengagement by radium. 30 

Heiustadt 117 

Helium 52, 77 

Helium from radium 98 

Helium minerals 77 

Helium spectrum 84 

Heller 117 

Heinptinne, De 43 

Henning 76 

Henry 8, 10 

Hertz 5, 6 

Heydweiller 92 

Himstedt 66, 67 

Hofmann 9, 11, 114 

Hofmanu and Strauss 58 

Hofmann and Strauss, Broggerite 59 
Hofmaun and Wolf.., .. 60 



Hofmann and Zerbtm. .48, 50, 58, 98 

Holkin 129 

Holzknecht 120 

Huggins, Win. and Mary 83 

Hydrogen, color of light, produc- 
ed by electric discharge in 2 

Hydrogen, weight of atom 5 

Hyperaemia 133 

Idiosyncrasy of patients 131 

Impure radium, temperature 30 

Inactive thorium 1 7 

Induced radio-activity 87, 88 

Induced radio-activity, Hypo- 

. . 93 


Induced radio-activityexplana- 
tion of 


Influence of radium emanations ^ 
on bodies .................... " 

Intensity of the current, meas- 
urement of .................... 1" 

Intensity of radiation ........... 18 

lonization of gases ....... . ..... 7, 8 

Ionizer Piffard's spark ......... 151 

Ionizing rays ................... 95 


Javal ........................... HO 

Joachimsthal .................... 20 

Johanngeogenstadt .............. 20 

Joly ............................ 106 


Kauri gum, photographic action 
of Becquerel rays through ...... 13 

Kelvin ........... 11, 68, 96, 100, 105 

Knett ........................... 65 

Kunz ................. 1 ....... 24, 34 

Kunz and Baskerville, Tiff any ite 
diamond ...................... 34 

Kunzite ...................... 30, 74 

Laborde ............... 30, 31, 96, 100 

Laborde heat .................. 96 

Laborde Impure radium, temper- 
ature of ...................... 30 

Lake (Stahmer & Co.) patent. .. 61 
Larmor ......................... 109 

Law for unconflned spaces ....... 91 

Le Bon ........................ 9 

Lernly .......................... 51 

Lenard ........................ 5, 6 

Leuard rays .................... 6 

Lenard's tube .................. 6 

Lichtenthaeler .................. 63 

Lieber ........... . . 125, 133 

Lieber's aluminum tube for ra- 
dium 125 

Lieber's apparatus for application 

of radium compounds 133 

Limiting current 18 

Lockhart 74, 77, 101 

Lockwood 23, 25 

Lodge 142 

Lorentz 109 

Lower organisms 120 

Lowry 103 

Luniiere 9 

Luminescence 3 

Lupus patient, Danlos Ill) 

Lupus hypertrophicus 120 

Lyster 127 


Maclntyre 127 

MacKenzie 127 

Magnet, action of upon cathode 

rays 3, 77 

Magnetic field, action of upon ft 

rays 14 

Magnetic field, action of upon a- 

rays 15 

Mai de mer 138 

Manning 137 

Marckwald 27, 60, 61 

Marckwald, character of polonium 55 

Martiudale 105 

Mass of cathode rays 5 

Maxim . . .96, 97 

McClelland 90 

McClung 94 

McLennan 102 

McLennan and Burton 65, 66, 67 

Mechanical action of cathode rays 4 

Melauo sarcoma 122 

Mendel ejeff 29, 100 

Mendelejeff, at. wt. tellurium.... 62 

Metals, conduct of 87 

Method for showing disengage- 
ment of heat by radium 30 

Method of obtaining radiographs. 42 

Metzenbaum 92, 135, 140 

Metzger 51 

Meyer and Von Schweidler 38 

Mice 128 

Microbes 136 

Miethe 11 

Miner, H. S., radio-activity of th. 63 
Modern Crookes tube for X-Ray 

work 8 

Molecular change 103 


Moles 110 

Momizite 20 

Morton 122, 133, 139, 140 

Morton's method for saturation of 

water with emanations 139 

Mouth 12 ^ 

Mucous Membrane, epithelioma. .145 
Muller 66 

Nagel 117 

Necrosis 121 

Necrotic ulcer 123 

Nerve cell disintegration from 

Becquerel rays 129 

Neuralgia 128 

Newtonian theory 5 

Nicol's prism 14 

Niobite 20 

Nitrogen, color of light produced 

by electric discharge in 2 

N C. uraninite (gummite) action 

through 12 

Norwegian gadolinite, orthite, etc. 49 

Norwegian gadolinite, etc 99 

Niewenzlowsky 9 

Optic Nerve 117 

Orangite 20 

Orloff 45 

Other sources of radio-activity.. 65 

Owens 69 

Oxygen, conversion into ozone, 

etc 44 

Oxygen, effect of radium on 44 

Ozone . .102 

Pacini 29 

Paillat 43 

Paralysis, facial 128 

Paul, Edward 139 

Pectolite 74 

Pellini 62 

Penetrability of radium emana- 
tions 33 

Penetration of radium rays 32 

Pegram 52, 87, 149 

Pentadecylparatolylketone 6 

Perrin 5, 43, 103 

Pfahler 145 

Pf eiff er 136 

Phillips 23, 25 

Phimosis scytitis 127 

Phosphorescence . 7 

Phosphorescence caused by eman- 
ation of radium 82 

Phosphorescing substances 10 

Phosphorus, ionizing, effect of . . . 19 

Photographic method 41, 52 

Photographic plate, action of Len- 

ard rays upon the 6 

Photographic plate, action of 

Roentgen rays upon the 6 

Photographic plate, action of 
phosphorescing substances upon 

the 9 

Photographic plate, action of 

"black light" upon the 9 

Photographic plate, action of 

flourescing substances upon the. 10 
Photographic plate, action of 

uranium and its salts upon the. 11 
Physiological action of radio-ac- 
tive substances 115 

Piffard rendering water radio- 
active (?) 93 

Piffard's Electroscope 150 

Piffard rays 148 

Piffard ray s skin 151 

Piffard rays uterine cancer 152 

Piffard's spark ionizer 151 

Piffard's ultra-violet lamp 149 

Pisani 21 

Pitchblende.... 13, 15, 20, 31, 53, 127 
Pitchblende occurrence of, com- 
position of 22 

Pitchblende, Bohemian 48 

Plant growth 116 

Plate Condenser 17 

Platinum-indium, Fusion of 4 

Platinum removal of activity of 86 

Plimmer 130 

Plucher 2 

Polarization 14 

Polonium 22, 47 

Polonium, a- rays of 41 

Polonium Precipitation of 26 

Polonium, methods of separation 53 
Polonium radiation less than ra- 
dium 53 

Polonium not new element (?)... 54 

Polonium nitrate 54 

Polonium radiferous bismuth .... 91 
Polonium rays photographic ef- 
fect 54 

Pozzi and Zimmerman 128 

Precht 28, 29, 31, 62 

Prescott 137 

Projection of rays 39 



Psoriasis 120 

Pusey 128, 129, 143 

Pzibram 20 

Quartz electric balance 17 

Quartz, photographic action of 
Becquerel rays through 13 

Radiant matter 4 

Radiation, intensity of 18 

Radiation from radium method 

of using 130 

Radiations of radinm 39 

Radio-active Elements, no. of.... 04 
Radio-active Elements method of 

distinguishing 64 

Radio-active emanations and sec- 
ondary radio-activity 69 

Radio-active lead 58 

Radio-active lead at. wt 59 

Radio-active lead chromate of... 59 j 
Radio-active lead spark spectrum 59 
Radio-active phenomena theories 

of 94 

Radio-activity a detectable prop- 
erty 30 

Radio-activity and magnetism. .. .108 

Radio-activitycause of 101 

Radio-activity Curie's theory. . .100 

Radio-activity, excited 85 

Radio-activity, Hypotheses for in- 
duced 93 

Radio-activityinduced ^ hypothe- 
ses 93 I 

Radio-activityother sources of. . 65 
Radio-activity Phenomenon capa- 
ble of measurement 18 

Radio-activity Simplest means of 

detection of (Note) 25 

Radio-activity Theory of 101 

Radio-activity of minerals com- 
pared with each other 20 

Radio-activity of uranium com- 
pounds compared with each 

other 19 

Radio-tellurium 60 

Radio-active Thorium 49 

Radio-diaphane 134, 135 

Radio-tellurium 60 

Radiograph of Al. metal by Bec- 
querel 12 

Radiographs of a fish 37 

Radiograph of gold fish 88 

Radiographs methods of obtain- 
ing 42 

Radiograph with pitchblende 

(Buckwalter) 15 

Radiograph with pitchblende (Col- 
lier) 13 

Radium amt. required 40.000 h. 

p. energy emission 81, 82 

Radium analgesic action 128 

Radium animal tissue, hair, bone. 

etc 118 

Radium at. wt. of 28, 29 

Radium Austria. United States. . 25 

Radium bacilli 136 

Radium bacterial cultures 136 

Radium B Diphtheria 137 

Radium-blood 139 

Radium capsule in between 

teeth 134 

Radium carcinoma of oesophagus. 121 

Radium chemical action 43 

Ujiilium chloride, bromide, etc. . 28 

Radium corneal opacity 118 

Radium curdling of milk 138 

Radium cutaneous lesions 144 

Radium deep seated diseases. . .134 

Radium "De emanated" 75 

Radium disengagement of heat 

by 30 

Radium eczema, psoriasis 124 

Radium Effect on Thxiringian 

glass, willemite, kunzite 30 

Radium epithelioma tongue 129 

Radium etiology of cancer 130 

Radium exhaustion 106 

Radium exposure 131 

Radium salts extraction 26 

Radium extraction and properties 22 

Radium eye 116 

Radium facial neuralgia 128 

Radium flexures cerebro-spinal 

system 128 

Radium germicidial agent 139 

Radium glacoma 118 

Radium guinea pigs, rattbits, etc. 119 

Radium Luminosity of 30 

Radium Lungs 138, 139 

Radium Hyperaemia 133 

Radium lupus . . 118 

Radium lupus, rodent ulcer, etc. .122 

Radium nial de mer 138 

Radium malignant diseases 122 

Radium mice 128 

Radium moles . ..116- 



Radium neoplasm, etc 129 

Radium nervous system 129 

Radium not an element (?) 

Wiukler 103 

Radium non-emanating 76 

Radium cancers, oesophageal ...135 

Radium optic nerve 117 

Radium Phirnosis scytitis 127 

Radium Plant growth 116 

Radium power dilating vessels.. 141 

Radium Preservation food 138 

Radium Radiations from 3 rays. 36 

Radium removal of hair 138 

Radium retina 117, 118 

Radium rodent ulcer 127 

Radium sclerotic 118 

Radium Secondary activity of... 43 

Radium seed germination 138 

Radium skin 116 

Radium Solar radiation 107 

Radium Spectrum 28 

Radium spine young animals. .. .115) 

Radium stricture 135 

Radium spasms 136 

Radium Temperature of impure 

salt 30 

Radium Transformation prod- 
ucts 113 

Radium Tuberculosis 

Radium ulcers 123 

Radium uterus, rectum and 

mouth 129 

Radium Wart 116 

Radium bromide and actinium 

oxide 57 

Radium bromide 300,000 activity 34 
Radium bromide action on plants. 136 
Radium bromide effect ^>hoto 

plate 29 

Radium bromide treatment 121 

Radium burn 116 

Radium Chloride treatment. .119, 128 

Radium clock Strutt's 105 

Radium D 114 

Radium E 114 

Ra-Em 103 

Radium emanations changes in.. 114 
Radium emanations, influence on 

bodies 78 

Radium exhibit at St. Louis 25 

Radium in treatment of skin dis- 
eases 124 

Radium preparations application. 122 

Radium sore, Becquerel 115 

Radium sore scar from . ..116 

Radium X 77 

Radium salts and heat 30 

Radium salts assumption of color 28 
Radium salts immersion of bis- 
muth, etc 55 

Radium salts physical properties 

of 27 

Railway tube 4 

Ramsay 141 

Ramsay electrons 112 

Ramsay extraction of active body 
like thorium from Ceylon min- 
eral 52 

Ramsay and Soddy 84 

Rassinghal and Gimingham 75 

"Ray" and corpuscles 36 

Rays Piffard 148 

Rays types 36 

R E 96 

Rectum 129 

Rehus 116 

Residual activity 86 

Retina 117 

Richartz 102 

Riecke, atoms 97 

Richartz ozone 102 

Rodent ulcer 127 

Robarts 127 

Rollins 119 

Rontgen 6, 7, 18, 85 

Rontgen's first tube 7 

Rontgen Rays. .6, 13, 18, 142, 145, 146 

Rontgen Rays and the eyes 117 

Rontgen tube 6 

Ruga scytitis 127 

Runge 28, 29, 31, 53, 111 

Runge and Precht emanium 62 

Rurio Jicinsky 144 

Rutherford heat effect of radium 


Rutherford Transformation prod- 
ucts radium 112 

Rutherford and Soddy, condensa- 
tion of emanations 79 

Rutherford and Soddy helium ... 98 

Rutherford radium D 114 

Rutherford and Soddy theory of.108 
Rutherford - fi rays and y rays. 101 
Rutherford and Thomson radium 

and uranium atom 100 

Rutherford vs. Curie 95 

Rutherford and McClung energy 

ionizing rays 94 

Rutherford disappearance radium 
emanation , . 91 


Rutherford and Barnes Heat 
emissions, etc., radium emana- 
tions 81, 89 

Rutherford activity dust particles 87 

Rutherford emanation X 86 

Rutherford and Soddy, helium 84 

Rutherford and Soddy condensa- 
tion temperatures, thorium and 

radium emanations . . . . ; 79 

Rutherford and Brooks emana- 
tion of radium 79 

Rutherford and Soddy effect 

moisture on emanations 75, 76 

Rutherford and Soddy emanation 

of radium sparked in glass tube 79 
Rutherford and Soddy emanating 

power of thorium 74 

Rutherford condensation of ra- 
dium emanations 74 

Rutherford thorium "emanations" 

69, 70 
Rutherford heat loss of earth 

and radium 68 

Rutherford and Allan excited ra- 
dio-activity 65 

Rutherford Thorium, power of 

inducing activity 51 

Rutherford and Soddy Thorium. . 50 
Rutherford uranium radiations 

complex 48 

Rutherford y rays 41 

Rutherford a rays 40 

Rutherford uranium a and ft rays 


Rutherford types of rays of ra- 
dium radiations " 36 

Rutherford electroscope 20 

Rutherford Law of conductivity 

of air 18 

Rutherford energy from uranium 16 
Rutherford and Soddy a rays. ... 15 

Rutherford uranium rays 11, 14 

Rutherford Rontgeu rays 13 


Saake 139 

Saginac 85 

Sarcoma giant cell 132. 143 

Samarskite 13, 20 

Saturation, current of 18 

Scar from radium sore. 116 

Schamberg 129 

Schenck, theory of radio-activity. 102 

Schmidt 19, 48 

Schmidt Nielsen . ..137 









Screen zinc, sulphide, barium, 

platino-cyanide . ............... 29 

Secondary Radio-activity ........ 69 

Secondary radio-activity of metals 85 
Septic ulcers ................... 127 

Sharpe .......................... 338 

Sichel .......................... 128 

Sidot ........................... 9 

Sidot's Blende eiiianium exp.... 62 

Skin effect radium on ........... 116 

Skiagraph of tools .............. 32 

Skin ............................ 115 

Skin diseases treatment of ...... 124 

Smolan De ..................... 11 

Soddy a rays .................. 15 

Soddy effect moisture on emana- 

tions ....................... 75, 76 

Soddy emanating power thorium 74 
Soddy emanation from radium 

sparked in glass tube, thorium 

emanations .................... 79 

Soddy helium .................. 84 

Soddy radio-active elements .... 64 

Soddy radium bromide ......... 71 

Soddy radium salt and tubercu- 

losis ...................... 138, 139 

Soddy Theory of, and Rutherford . 10S 
Soddy Thorium X ......... . ..... 50 

Soddy uranium radiations ...... 47 

Soddy uranium rays ............ 14 

Solar radiations and radium ---- 10(5 

Solar rays ...................... 146 

South American Mineral ....... 52, i)9 

Spark Ionizer, Piffard's. . . ...... 151 

Spasms ......................... 130 

Spies ........................... 11 

Spine ........................... 119 

Spinthariscope ............. 72, 73, 97 

Spinthariscope of Crookes ........ 72 

Spodumene ...................... 74 

Stahmer & Co. Lake. . ." ........ 61 

Staphylococc'us bacillus ......... 130 

Strauss ......................... 11 

Strauss lead sulphate, etc ..... 58, 59 

mercury ....................... 66 

Streptococcus bacillus .......... 136 

Strutt a rays .................. 40 

Strutt-^-emanations from metallic 
Strutt examination of minerals. 77 
Strutt y rays .................. 42 



Strutt radiations of radium 33 

Strutt's Radium Clock 105 

Sudborough 44 

Sulphides emissing ft rays 55 

''Tailings" 23 

Tantalite 20 

Taudin and Chabot 103 

Temperature, effect of upon the 

radiations 18 

Theory, electric single fluid of 

Franklin 5 

Theories of radio-active phenome- 
na 94 

Therapeutic application radio-ac- 
tive substances 115 

Thompson, S. P G 

Thomson Cambridge tap water ... 65 
Thomson cause emission of en- 
ergy from radium... 96 

Thomson Crookes ray 5, 104 

Thomson radio-active matter, 

Becquerel's Hypothesis 94 

Thomson Radiation of metals. . . .106 

Thomson Rontgen rays 13 

Thomson and Rutherford laws of 

conductivity of air 18 

Thomson and Rutherford ura- 
nium atom and radium 100 

Thomson, Larmor and Lorentz 

atom complicated 109 

Thorium 36, 41, 48 

Thorium and radium de-emanated 75 

Thorium and septic ulcers 127 

Thorium "de-emanated" 75 

Thorium emanation X 87 

Thorium from mouazite and con- 
stituents 52 

Thorium from South American 

Mineral 52 

Thorium inactive 107 

Thorium, occurrence with ura- 
nium 19 

Thorium radio-active 49 

Thorium radio-activity of 19 

Thorium radio-active from mona- 

zite 52 

Thorium X 49, 77 

Thorium X Rutherford's 107 

Thorite 20 

Thuringian glass 30. 74 

Tiger eye, photographic action of 

Becquerel rays through 13 

Tiffanyite 74 

Tissue 119, 130 

Tissue, hair, bone, etc 118 

Titanium separation 56 

Topler pump 112 

Tongue and tonsil 129 

Tonsil and tongue 129 

Tourmaline 14 

Townsend 18 

Tracy 138 

Transformation products of ra- 
dium 113 

Transmutation Ill 

Traubenberg 67 

Troost 9 

Tuberculosis 138, 145 

Tuberculosis, germicidial agent 

for 139 

Tumors 145 

Tur 120 

Turquoise, photographic action of 

Becquerel rays through 13 

Ty phosus bacillus 13(5 

Tyrer 52 


Ultra violet rays 146, 147 

U. S. Geog. Survey Expert (Kunz) 24 
Urauinite (See also Pitchblende), 

12. 13 

Uranium activity by the electro- 
meter 36 

Uranium 41, 46, 53 

Uranium certain minerals possess 
a greater intensity than the 

metal uranium itself 2.1 

Uranium extraction of from 

"Tailings" 23 

Uranium, metal 20 

Uranium occurrence with thorium 19 

Uranium radio-activity of 19, 51 

Uranium radio-activity not con- 
stant 47 

"Uranium rays" 11 

Uranium residues 26 

Uranium salts of in sunlight.... 11 

Uranium and thorium 21 

Uranium compounds, activity of 

different 19 

Uranium, metal 20 

Uranium, potassium, sulphate.... 10 

Uranium salts 10, 11 

Uranium salts, activity of, a rays 16 

Ur, Ur X,*Ra Em, etc 103 

Ur X 47 

Uterus . ...M29 



Vaii Aubel 43 

Van Buren 137 

Velocity of cathode rays 5 

Villard 41 

Voller 67 

Von Lerch . 87, 93 


. 70 
. 27 
. 63 







Welsbach Light Co 

Wilson 41 

Wiedemann 3, 5, 150 

Wiedemann, Luminescence 3 

Wien 36 

Wigham 136 

Wilbert 144 

Willcock 45 

Willemite 30, 148 

Willemite and calcite 147 

Williams 123, 130, 133, 143 

Wilson, C. T. R 65 

Wilson, W. E 100 

Winkler 103 

Winkler and Hofiuanu 60 

Wolf, radio-active lead 60 

Worms . ..120 

Xenotime 20 

"X-light" 143 

X-Rays 6, 94, 145, 140 

X-Rays Carciuomata 145 

X-Ray cancer 146 

X-Ray epithelioma mucous mem- 
brane 145 

X-Ray Lupus, acne, etc 146 

X-Ray sarcoma 143 

X-Ray treatment 131 

X-Ray treatment (Williams) 143 

X-Ray tuberculosis and carcin- 
nouia . . 145 

Zeisler 146 

Zerban 9, 52, 99 

Zerban activity thorium 48 

Zerban at. wt. actinium (?) 58 

Zerban Primary activity thorium 50 
Zerban South American Mineral. 52 
Zerban Th. from S. Am. Mineral. 99 
Zerban thorium from uranium.. 98 

Zimmern 128 

Zinc Sulphide 74 

Zinc sulphide, phosphorescent 9 

Zinc sulphide, hexagonal 9 

Zinsser ..137 

-.- '''"* 


This book is DUE on the last date stamped below. 


P^**^***** j ftj**' " u " *** 

;'5O cents on foi 

OCT14 1947 




LD 21-100m-12,'46(A2012si6)4120 



AUG 3 1962 



1 U /U4 

YC 10794